1. Cone snail

The cone snail is one of the most venomous animals you could possibly encounter in the wild. What makes matters worse is that it has an absolutely beautifully colored shell. What this means for tourists diving or snorkeling in the waters it inhabits, then, is that they might reach down to touch it without really understanding the potential consequences. 

Tiny but dangerous and lethal shell
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There are hundreds of species of cone snail, all of which are poisonous. Those that live in the U.S., however, don’t cause any harm to humans (lucky us). Elsewhere, though, their harpooning tether will paralyze and kill anything it touches. For unlucky tourists, these areas include the beaches of the Indian and Pacific Oceans. Watch out for these pretty shells while swimming about. 

2. Box jellyfish

Box jellyfish have become notorious for their tiny elusive bodies and deadly painful stings. Nets, for instance, have been installed around many Australian beaches to try and prevent the things from inhabiting areas that people frequently swim in. The efforts have only had some success, however. Given that the thing spans a greater area than just Australia, it can still ruin your vacation. 

Sign, warning of the deadly box jellyfish, in Australia.
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Other locations in which you can find the box jelly are places like Thailand and Indonesia. Given that these places are exceptionally popular beach-going destinations, the box jellyfish is definitely something that might ruin your stay overseas. Just know that if you plan on swimming in an area with the box jelly, you should be prepared for the worst. 

3. Puffer fish

The puffer fish is a beautiful fish. It’s as if you extracted a cactus from Arizona’s Sonoran Desert and threw it into the sea. Then, from there, it evolved to explode its girth and insert its horrible needles into whatever prey or predator antagonizes it. Oh, and we forgot to mention, its quills are also horrendously poisonous. 

Yellowspotted burrfish using its defense system
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The places in which you’re likely to find a puffer fish are often close to coral reefs. And, in case it wasn’t already clear to you, coral reefs are tremendously popular tourist destinations — especially for those who like to swim. So if you’re spending some time in the Great Barrier Reef of Australia or some other reef, be wary of these puffy foes. 

4. Brain-eating amoeba 

You’re extremely unlikely to encounter a brain-eating amoeba at any point in your life. However, there is a remote possibility. And why, exactly, is this? Well, because the thing likes to hang in hot springs and other warm bodies of water. The first few documented cases, for instance, occurred in an Australian lake, where small children were exposed to the amoeba. Once they contracted the amoeba, it was game over. 

UMass Amherst

The amoeba starts feasting on your brain once it enters your nose through the nostrils. From here, it can surround your brain in the cerebral spinal fluid. From there, there is essentially no hope. If you want to avoid the thing, then, you’ll want to keep your head above water when you suspect they might be around. Good luck. 

5. Poison dart frog

Poison dart frogs aren’t something that you will often encounter on your vacations. Yet, if you are traveling through the rain forests of Costa Rica, you just might. And, if you do, you might accidentally come into contact with their horrendously poisonous skin. This skin, once it touches yours, gifts you with a hefty dose of what you’d rather not have. 

The Amazon dart frog is bright,colorful, frog species found across the Amazon in Brazil,Colombia,Peru and Ecuador.
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Curiously, the poison on the poison dart frog doesn’t develop when the thing is isolated from its environment. This peculiar fact suggests that there’s something that happens in the frog as it’s developing that enables it to develop its deadly taste. If you see one of these things, you should start screaming and running in the opposite direction. These guys have a penchant to kill.  

6. Blue-ringed octopus

The blue-ringed octopus is one of the most notorious ocean predators we have on this list. While it’s small, it is extraordinarily venomous. If you see one of these things, what with its beautiful blue rings, you should swim out of the water and run home. Only there will you be safe from this horrid and man-killing beast. 

Blue-Lined Octopus, Hapalochlaena fasciata, endemic, Sydney Harbour, Sydney, New South Wales, Australia, South Pacific Ocean
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Unfortunately for us, these things are found in tourist spots the world over. You can find them off the coasts of Japan, for instance. You can also find them in Australia — but we all knew this, because Australia is by and large a terrible place full of terrible creatures. Any way you spin it, you do not want to run into this thing while engaged in your vacation snorkeling experience. 

7. Lionfish

The lionfish was given its name for a reason. And this reason is in two parts. First off, the thing kind of looks like a lion (OK, marginally). Second, the thing is almost as ferocious as a lion. However, unlike a lion, this creature is likely to destroy your otherwise-perfect vacation. Found all over the Indian and Pacific Oceans, these things will positively ruin your trip.

Common Lionfish {Pterois volitans} is an invasive species in the Caribbean. Bahamas, December
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The lionfish likes to hang around coral reefs. Fortunately for us, they are not the most aggressive. So, if unprovoked, they might just leave you alone. If you get too close, however, consider it game over. A quick prick by one of the few spines that adorn this lion-of-the-sea’s back and you’re done for. Yikes. 

8. Indonesian needlefish

The needlefish is an unlikely killer. It’s not that aggressive, and not that bloodthirsty for human flesh. On occasion, however, the thing will find itself flying through the air like one of the most lethal and gill-using of foes. The body shape of the needlefish is what makes it so deadly. If it flies in your face, you will die. 

Instagram via @chrome_killers

Why? Well, because it is thinly shaped, like a needle. There have been a few instances where the thing has jumped into the air and flown through peoples’ chests. On occasion, this has killed. If you’re enjoying a vacation out on the open sea, then, you might want to watch out for this foe. It flies fast and swift. You’ve been warned. 

9. Sea snake

Sea snakes are one of the most venomous animals on Earth. Because of how venomous they are, they have earned a sterling reputation as one of the most venomous animals around. And because of this, you will surely want to avoid them on your next vacation. Unfortunately, such a thing is not always possible. 

One Banded Sea Krait (Laticauda colubrina) close-up underwater. Also known as yellow-lipped sea krait and colubrine sea krait. This highly venomous sea snake feeds on small fish and eels. It must breathe air and so comes to the surface frequently, before swimming back onto the reef. The location is Phi Phi islands, Andaman Sea, Krabi, Thailand.
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The places that the sea snakes like to call home are also places that many of us like to travel to for our lovely beach vacations. You can find them, for instance, off the West Coast of the United States. This is terrifying. While you’re more likely to find the things meandering about the east coast of Africa, you’d best be careful elsewhere. 

10. Stonefish

The stonefish is considered the most venomous fish on Earth. This is troubling. It’s made especially troubling given that the thing is found in many places that we think of as tropical paradises. In Brisbane, for instance, a touristy spot in Australia, a woman was recently hospitalized from an unfortunate encounter with the fish. 

A well-camouflaged stonefish, Synanceia varricosa, lays under the sand in Raja Ampat, Indonesia. This area is known for its amazing marine biodiversity and is a popular destination for scuba diving.
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The stonefish looks kind of like a stone (which likely could have been assumed from its name). So, if you’re one of those divers that likes to look around the bottom of the ocean floor, you might want to be on the lookout for this stony-looking fish. If you mistake it for a stone, it might be the last mistake you ever make. Be thankful we warned you. 

11. Moray eel

There is something around 80 different species of moray eel. Each is more likely than the last to destroy your vacation. And why, exactly, is this? Well, because the things have a vicious penchant for human death, of course! OK, not really. But in all seriousness, these things exist in abundance in places where humans like to vacation. This had led to more than one unsavory encounter. 

Nein sie will niccht beissen.
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The areas you’re most likely to find the thing are in the tropics and subtropics — and in particular, the Caribbean Sea. So if you’re looking for some of those limpid warm waters, you might want to make sure you check before this vicious little killer takes a bite out of you. What makes matters worse is that the eels are slimy. So more than just attack you, they’ll leave you with a bit of slime. Gross. 

12. Indian scorpion

The Indian scorpion is notorious for being the most venomous scorpion on Earth. Because of this, it has ruined numerous vacations to the Indian region. This is a primary concern for those looking to bask in the Bali sun. The scorpion stretches in length to be about 1.5 to 3 inches in length. This is relatively large compared to other scorpions. 

Indian Red Tail Scorpion, Hotenttota tamulus, Saswad, Pune District, Maharashtra, India
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Oftentimes, the way in which tourists and locals will encounter this thing is the stuff of nightmares. First, it will seek refuge in the warm house you’re likely staying in. Then, as it crawls its way across the ceiling, it will sometimes fall to the bed in which you and your significant other are staying. Then, after it crawls into your sheets, it’s game over. 

13. Koala 

Koala bears might be one of the better known creatures that tourists know to watch out for. They have a nasty reputation for their pugnacious and temperamental demeanor. They have often found themselves drunkenly getting into fights with the local gringo. OK, while fistfights aren’t necessarily likely, the things will attack you. And they have claws. Yikes. 

Koala mom and baby cute animals dark truth
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And, like with all marsupials, this thing is most likely to attack you when you’re visiting Australia. Here, the things maraud and pillage daily, pestering and plundering the lands. Their imperial dispositions are unsettling, to say the least. Fortunately, if you see one, you can stay well out of its way without it trying to attack you. Thank goodness. 

14. Kangaroo

The kangaroo is another of the animals that have a rotten attitude toward life. Because they feel so dejected all the time, they take out their troubles on the tourists that come through. And, like with a few of the other animals on this list, the kangaroo has roaming territory primarily on the continent of Australia. 

kangaroo that looks extremely and unnecessarily aggressive
Wikimedia

This means if you plan on making a visit to the Great Barrier Reef or the rain forests of Queensland, you will have to deal with a few of these unsavory foes. They literally have a pugnacious disposition, and will use their tail to help them kickbox their enemies. This isn’t good, considering that a kick from one of these guys can be devastating. 

15. Africanized bee

The Africanized be is one of those things created for one purpose, then released upon the world (by accident) to wreak havoc on all that are near it. Unfortunately, this thing has been a hazard to both tourists and locals in the southern United States. What makes the bee so excruciatingly pestering is its aggression. Unlike other bees, this one will seek out and attack any near to the nest. 

Bumblebee in flight front view with blurred leaves background close up.
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Attacks have been reported where someone was 100 feet from the site of a nest! What’s worse is that these things will follow you to ensure that you are not a threat. This can entail a chase that lasts over a mile. And, to top off this horrible cocktail of unfavorable traits, the stings are enough and in great enough number to kill most people. Yikes. 

16. Southern African spitting scorpion

If something venomous has the verb “spitting” in its name, you know you should probably avoid it. The reasons for this should be as clear as the reason you’re loath to visit your mother-in-law: It’s a viperous creature that is venomous on its own. If it can shoot its venom from a distance, that makes it a thousand times worse. No thanks. 

Head to head portrait of a scorpion creeping towards teh camera over small stones
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So, just like with your mother-in-law, the southern African spitting scorpion is liable to ruin your vacation. The thing can be found, as its name suggests, in southern Africa. So if you’re looking to visit some of the place’s beautiful beaches or stunning archaeological sites, you might want to consider bringing a face mask. This scorpion could definitely ruin your day. 

17. Fire ant — Orlando, Florida

Have you ever thought of taking a visit to Orlando, Florida? Neither have we. Regardless, many people have this as a go-to destination primarily because it holds a very famous tourist attraction: Disney World. But there’s another thing that exists in a great abundance in Orlando: fire ants. And if you’re in the know, you’ll understand why this is terrifying. 

Red Imported Fire Ant, Ant, Animal, Insect, Stone - Object
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Fire ants, much to the chagrin of everyone who’s ever encountered them, are terrifying little beasts. While only one or two are not bad, a handful can be a problem. The things leave you with little prurient red sores that suppurate and fester. No good. If you get stung by too many, you can actually be envenomated to the point of death. Be wary. Be very wary …

18. Bear

Bears are a fact of life in many places. If you’re visiting beautiful British Columbia, for instance, bears are something you’ll see all of the time. Many bears, however, don’t cause too much of a problem. Others do. These bears are likely familiar to you — the grizzly and the polar bear. Fortunately, we don’t encounter these too often. 

STANDING LOOKING IN WINDOWS OF CAR YELLOWSTONE NATIONAL PARK WYOMING USA
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Some vacations, regrettably, have been ruined by these bears. While enjoying a nice camping trip, many unfortunate groups have had the rude awakening of a bear tearing through their camp, stealing their things. Others have themselves been attacked. Ultimately, you’ll want to exercise extreme caution when traveling in areas commonly known to house bears. 

19. Feral cat

Singapore is a futuristic haven for many looking to enjoy the city life. And for this, it is a place that many have made a must for their future vacations. Singapore also has some problematic animals, however. One of the most well-known is the feral cat. While many cities have feral cat populations, Singapore stands out for a reason. 

Portrait of shot of cat family living in the nature.
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For whatever reason, the cats in Singapore are equipped with a malicious gangster attitude. They set up roadblocks and often take tourists hostage. This is no good if you appreciate that thing called “freedom.” OK, in reality this doesn’t happen. Duh. But what does happen is the occasional attack. And, if you don’t like rabies, you should probably try and avoid these things. 

20. Sea urchin

Sea urchins are extraordinarily common in seas around the world. One of the most common, as it turns out, is also the most deadly. Yikes. What this means for the would-be traveler is that they need to be extra cautious when diving in certain locations. Here, the diver could encounter a not-too-pleasant experience when taking underwater photos. 

walk on a sea urchin at the beach
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When you step on a sea urchin, the results are unfavorable. First off, the thing will stab into your appendages. From here, you will actually have to try and remove the thing from your skin. This is regrettable, as the spiky sponge is covered in bristly and uncomfortable stingers. You want to avoid these things as thoroughly as you can. Good luck. 

21. Stray dog

Like with what we see in a few other places, Indonesia has its fair share of feral animals. And these, if you’re not careful, can make your vacation a bit unpleasant. There are several reasons for this. For one, the dogs can be vicious and unforgiving. Ultimately, they will attack you and give you rabies. This is unlikely to be something you were seeking on your vacation. 

Stray dogs on street makes fear people
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This is made especially unpleasant considering that Indonesia is a hot spot for those looking to enjoy the beautiful natural scenery. If you want volcanoes and waterfalls, for instance, you probably don’t also want stray dogs. What makes matters worse is that they breed and then have more babies that will go out and spread the problem. Ugh. 

22. Monkey — Thailand

Thailand, while hosting some of the most beautiful and stunning beaches on the planet, also hosts a few species of wildlife that are well-equipped to ruin your vacation. One of the more prominent of these is their monkey population. The most common species of monkey in Thailand is the macaque. And macaques, in case you didn’t know, are notoriously vicious. 

Monkeys waiting for food in Monkey Beach, Phi Phi Islands, Thailand
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If there were a specified scoundrel of the primate lineage, the most plausible candidate would be the macaque. The little monkeys have a strict hierarchical society in which fighting takes the place of common courtesy. Don’t expect one to hold the door for you. Anyway, if you’re in Thailand, watch out for these guys. They can be vicious. 

23. Mosquito

In the United States, mosquitoes can be an extraordinary nuisance. In other parts of the world, however, they can be extraordinarily deadly. This is for several reasons. The most salient of these is that they act as a disease vector. This is bad. In places like Africa, for instance, you can get horrible diseases like dengue fever and malaria. 

Twitter via @combatadengue

Considering that these diseases kill a whole lot of people per year (especially in undeveloped parts of Africa), this is terrifying. Fortunately, as a traveler to such places, you can get vaccinations in prep for any such trip. Still, however, you will want to make sure to protect yourself as well as you can against the flying little pests. 

24. Great white shark

The great white shark is one of the (if not the) most formidable foes you will find in the ocean. The thing is great, white, and a shark. These are all bad when accompanied by three rows of terrifying teeth literally evolved to tear through the toughest of animal skin. Considering this, being mistaken for a seal while on vacation would not be ideal. 

Great white in Gansbaai, South Africa, Dangerous beach, Shark Alley
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Great whites can be found roaming the waters of a great many places. Of these, some are major vacation spots. Many beaches in California, for instance, have shown a great prevalence of great whites. Many, in fact, have had reported attacks. These are bad. Very bad. You should do your best, then, to try and not look like a seal while swimming about these shark-infested waters. 

25. Barracuda 

The barracuda is another of those creatures that you should fear with everything you can possibly muster. And why is this? Well, because the band Heart wrote a song about them in the 1970s. OK, not really. But the animal is notorious for its proclivities toward violence. If you see the things in their natural habitat, they will likely try to instigate a street fight. 

Tropical and subtropical saltwater fish the barracuda is a ray-finned fish known for its large size and fearsome appearance
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The barracuda can be found in touristy spots around the world. Of these, the most famous are probably the Pacific and Indian Oceans. Here, your fun time on the beaches of Bali may be interrupted by one of the most ferocious fish in existence. Let’s try and prevent that from happening by staying safe in the waters. Good luck!

26. Hookworm

Living in an environment with horrible parasites isn’t really anybody’s idea of a good time. However, this is unfortunately the plight that certain locals of Punta Cana in the Dominican Republic have to deal with. And even more unfortunately, this is something the tourists to such areas have to deal with as well. 

Tapeworm is a freshwater fish parasite under the microscope for education.
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Here, people have contracted the horrible (and many might say disgusting) hookworm. This parasite first infects you with a tormenting itch, then moves to a blistery disposition not for the faint of heart. The most regrettable is that all it takes to succumb to infection is a nice little walk on the beach. Considering this is a thing to do for tourists, the hookworm can definitely ruin your vacation. 

27. Japanese hornet

The Japanese hornet is one of the most formidable stinging beasts in the world. While it doesn’t measure up in size to the Meganeura, a giant species of griffinfly that roamed the land hundreds of millions of years ago, the thing is quite large. And so, a few stings from this bad boy and your Japanese vacation will swiftly get cut short. 

A Japanese paper wasp feeds from wildflowers beside a river in Kanagawa, Japan
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So, if you intend to experience some of the delicious cuisine or beautiful volcanoes that fill the small island, consider a way to try and protect yourself from this flying insect. The thing is also horribly venomous, so its sting is not something you’ll want to embrace. In fact, the stinger is a quarter-inch in length. This is disturbing to say the least.