A blue ringed octopus - they're a cute looking tiny octopus but quite capable of killing a human.
What's worst is that after getting bitten by one you will be mentally alert but completely unable to do anything as you feel your body just stop doing things that keep you alive (like breathing)...
Otter. They're a bunch of water gangster, they are fierce and they will bite. Even crocodiles and snake fear them when in group, human should leave them alone. Freaking cute creature though i just wanna pet one.
A big cat, any of them really. They look so cute and I’d have my guard down because of how much they remind me of little cats. And then boom it’d hit me, they might be running the same Cat Brain OS but they’re capable of taking me out in one swift swipe if they wanted to and if I accidentally irked them somehow (also not having any positive attachment to humans they might not hold back). But it’d be too late, and I’d die terrified but also beholding the cute, cute kitty.
The Blue Ringed Octopus is a cutie. Tiny little guy, you could just scoop up with your hand.... has one of the most potent toxins on earth, and there is no antidote.
Slow loris. They have this look like they're scared and want to be cuddled, and if they could speak, they'd probably say "Oh my, did I forget to tell you I'm the only poisonous primate?"
A whale. They're not particularly aggressive, but their normal motions have the potential to shatter every bone in your body if you approach them wrong, like if you approached them where their tail ends up hitting you. That and I imagine you'd have to be able to swim to approach them in the first place without being terrified, so that rules me out.
Dogs. They're the one animal I can actively get close to daily which depending on upbringing can either be very loving and sweet, or absolutely territorial monsters.
When I was in high school there was one of those dogs, he'd bark lightly, or his front paws on the picket fence and wag his tail extra hard, which are normally signs of wanting to be pet, except if you got within petting range he'd go for a bite.
Cat's at least get away from you if they don't want attention. I've learned more about dog body laungauge since high school, but I've also been bitten since then on just a random walk by (not going for a pet) just as the owner was saying it didn't bite. It did.
Though I suppose terrified it's a bit much. Wary is more like it.
Bats. Some species really look like adorable little sky kittens. But they are also significant disease carriers, ranging from rabies to ebola. Bats themselves have evolved to be immune to things that can kill us and other animals.
It’s why you should never, EVER touch a bat. Just don’t.