Mine would have to be my dog when she was a puppy running around my couch 20 times whenever somebody "new" entered the room. Now how about your stories?

kinda messed up but once my dog did a poo turned around and started eating it...wtf?

My hamster used to curl up and roll around...

My hamster would push the rolling ball instead of riding.
And my dog likes to lick the walls

well, my rabbit fell down stairs, ate one of my doughnuts, chewed through 3 psp chargers and a sega genesis and finally, he chewed through our phone line causing us to upgrade to high speed.

he died of cancer about 2 years ago, ah well, it was fun while it lasted.

My cat opens his jaw and closes it rapidly when he sees birds. It's kinda cool/disturbing.

my dog attacked me while i was going to school! and ripped my shirt.

My cat vomited and started to eat it.

After this I kept the lazer away from her. She went nuts over it...

My pet failed to exist :P