A skin condition commonly found in the elderly and those who have just come out of the bath where their skin is wrinkly and squishy, similar to the bun of a hamburger that has been in the fridge for too long.
1) "Hey, look at that old geezer's Fridge Burger! You could slingshot with that!"
2) "I just got out of an hour-long bath and damn! Worse case of Fridge Burger I'd ever had."