They'll be laughing too hard to bother attacking you!
The Drop Bear - Found in Australia. Sits high up in trees waiting to drop down on its prey and attack it. Looks like a large, angry koala. Be Afraid! (*This might just be a myth... or it might be real.... who knows?) This design would be perfect for pyjama pants. Especially if you are camping in Australia. After all, the drop bears are going to scare them off anyway!