you get a package in the mail for a new dog collar. You ordered it online, not suspecting anything. When you open it, there's two collars. One is green, the other blue. Since you didn't read the package, you totally missed the fact that if you put on the collar, you will transform into a dog, and if you put the collar on your dog, he will transform into a human.

"Woof!" Your dog happily barks, jumping onto bed with you.