Possums are wild critters. Not only are they the only marsupial found north of Mexico, they play dead so convincingly that they actually excrete a horrible smelling odor from their anus that makes them smell like a corpse. Cool! Studies have shown that possums actually have better memories than dogs, rats, cats and pigs when it comes to remembering where food is. And if these stinky weird food remembers aren't already strange enough, they're immune to almost all snake venom.