Even though these huggable animals may seem like the cuddliest creatures in the world, they’re a lot more dangerous than you think. They’re marsupials with powerful jaws that give an intense bite. They’re not afraid to use their jaws when they feel threatened or cornered, so don’t think about giving them a big hug. Attacks are rare, considering they sleep 22 hours per day and sleep in the trees, but if you do spot one, try not to startle them. The most unnerving part about koalas, though, is that they can transmit chlamydia to a human who comes into contact with their urine. They’re also known for being more aggressive than crocodiles (via Best Life Online).