-the little annoying piece of skin that peels at the bottom corner/side of your fingernail
-usually on the thumb
-can be peeled/ripped off with your other fingernails (usually the pointer finger on the same hand)
(not to be confused with a cuticle
"Dude, I've had this incapacitator on my thumb ALL week and it's really starting to piss me off cuz i can't stop picking it!"