A porcupine hangs on a willow tree branch, Alaska

© Design Pics/Danita Delimon

Psycho quiller!. Porcupine

Psycho quiller? Nope, this is no homicidal rodent. Act friendly and keep a tail's length of distance, and you should be safe from a spiny fate. (That thing about porcupines launching their quills at you like darts? Yeah, total myth.)

But make no mistake: These pudgy rodents are more than able to put the hurt on perceived predators. Porcupine quills are lined with barbs that make them difficult—and extremely painful—to extract. Even the burliest bear or the toothiest cougar fears a snoutful of spines, so most stalkers of forest prey are content to leave Spike here alone.