Give Yourself Goosebumps Beware Of The Purple Peanut Butter Book 6

Your aunt and your uncle told you to stay out of their basement. So, of course you check it out. That's where you find the dusty old refrigerator. In the fridge there are two containers, one has purple goop. It smells just like a peanut butter-and-jelly-sandwich. The other holds a piece of chocolate cake. If you eat the purple goop, you start shrinking and if you eat the cake, you grow into a tall giant. Now you're trying to escape from the police who are convinced you're a mutant alien.