Erwin Schrödinger is speeding down the highway one day when a cop pulls him over. While he's asking Erwin for his license and registration, he notices that Erwin is sweating and acting kind of twitchy. The cop spot checks the car and sees nothing suspicious and then asks Erwin if there's anything in his trunk. Erwin replies, yes, I have a cat in the trunk. The cop replies, really, can I check it out? Erwin says, go right ahead.
Accordingly, the cop goes and opens the trunk and exclaims, "That cat is dead!" Erwin replies, "Well, it is now."