Rat King, Pale Piper is a rare Legendary Creature — Rat Avatar card from Teenage Mutant Ninja Turtles Eternal (TMC), collector number 19. Current market price: $0.32 (foil $2.00), TCGplayer market prices via Scryfall.
Menace Whenever Rat King or another nontoken creature you control leaves the battlefield, create a 1/1 black Rat creature token. {2}, Sacrifice a token: Draw a card.