Who knew?

Platypus  

The platypus looks, for all intents and purposes, like a joke. A slapped together set of features and parts of other animals, evolving in the island obscurity of Australia. Wait, what country? Oh you know exactly where this is going now...that's right, even the comically misshapen platypus will do you in. For all their bumbling charms, platypuses have a number of points in their favor. Firstly, they're damned fast swimmers. They can also hunt their prey by detecting the electrical fields generated by their muscular contractions. That's right, they can track by telltale signs of your body's electricity. How badass is that? Not only that, but the Platypus is one of the few venomous mammals to be found. Only the males pack this heat, on the spurs of their hind legs. While it's powerful enough to kill animals around the size of a dog, it won't kill you. But you might just wish it had. The pain is so excruciating that it's completely incapacitating, and can last for months. You also get edema, starting at the site of the wound, and then rapidly spreading. That's when weird fluids building up beneath your skin, making the effected area all swollen and lumpy.

from  15 Cute Animals That will cause you horrible harm