There are some animals that we instinctively know to stay far away from. Either due to their imposing size, insane speed, raw strength or the fact that a single, quick bite could put us six feet under. But there are others that tend to get underestimated when it comes to the damage they could cause. Maybe it’s because they don’t appear intimidating at first. Here are a couple of animals who under no circumstances, you should mess with.

1. Assassin Bugs

The name says it all. This insect can and will take you down, but not in the way you think. At worst, their bites are mostly just irritating and itchy. But what will send the grim reaper your way is the parasite it carries which causes the deadly Chagas disease. Nearly 7 million people, mostly from South America, get infected every year and those who survive are left with serious heart problems and neurological disorders. So, tread carefully when it comes to his tiny bug.

2. Alligator Snapping Turtle

They may be slow-moving on land, but if you know what’s good for you, you’ll stay far away from their mouths. They may not have sharp and dangerous teeth but they do have powerful beaks that help them bite and chew foods. And the alligator snapping turtle has an exceptionally strong one. Its bite measures at a whopping 1000 pound per square inch (psi) and while it’s not in the same league as an alligator’s (3700 psi), it definitely ranks higher than a great white shark’s (625 psi). Get the picture now? LEAVE. THEM. ALONE. Unless you’re ready to lose a finger or two.

3. Tiger Centipede

A standard centipede bite is already very uncomfortable – pain, itchiness, redness and swelling are all to be expected. But the pain from the bite of a tiger centipede or giant desert centipede is unimaginably awful, even worse than that of a bullet ant or tarantula hawk wasp. According to Naturalist Coyote Peterson, who has a reputation for working his way through the “Insect Sting Pain Index,” the tiger centipede bite absolutely eclipses all the insect stings he has ever experienced. And painful insect bites are not at all new to him.

4. Moray Eels

Moray eels are scary-looking eels that usually hang around reefs and rocky parts of shallow waters in search of passing prey. There are at least 200 different species and they all possess razor-sharp, needle-like teeth that are arranged in a backward-facing fashion. Could you imagine getting your hand stuck in one of these things’ mouths? Unpleasant would be an understatement. They not only sink into your flesh but tear it apart as well, allowing their venomous mucus in. This causes your red blood cells to clump up and eventually destroying them.

5. Giant Anteaters

Anteaters are generally calm, fuzzy and adorable creatures who spend most of their time searching for tasty ants. But they are equipped with powerful claws that they primarily use for digging – until you mess with them, that is. Then they’re clawing at you and not the ground. Two Brazilian hunters learned this the hard way, after they were both killed by anteaters in 2010 and 2012 respectively. An Argentine zookeeper also fell victim to one while she was in the enclosure with an especially aggressive anteater. Seriously, those claws are something else!