Of Dr. Seuss fame, a large yellow bird that may or may not have a blue star on it's belly.
Colloquially a person or thing that offends. Can also be an event that pisses you off.
"That no star Sneetch!"
"Dude! Your mom just got sent to Auschwitz!!!"
"Ha ha! I replaced your shampoo with actual poo!"
"You fucking Sneetch!"
"We're gonna be late for the plane!"
"Corrissa wrecked your car"
"That sneetch ass motherfucker!"
"Who's the Sneetch that ate all the popcorn?"