Yeah, it's a glitch. It happened to one of my pets about a week ago, I filed a ticket.

Hm... I don't think it's a glitch. I've been zapping my pets everyday twice a day from both zappers since the beginning of the school year, and this has happened to me tons of times. I think its just a cool new feature that's been added, because if it wasn't then they probably would have changed it by now.

Whoa, awesome! Glitch or not, you got one of the best pets, that's for sure. ;D Have fun with him!