The platypus is a very unusual animal found only in Australia. It lays eggs, but it is not a bird. Platypus and echidnas are the only two animals that lay eggs. The male platypus can inject you with venom from a spur on its hind leg, but it is not related to the snake.
Platypus are found in waterways, and are very good swimmers. They grow to about half a metre long, and are dark brown with a rubbery snout, very much like a duck's beak.