Gutter Grime is a rare Enchantment card from The List (PLST), collector number ISD-186. Current market price: $1.43, TCGplayer market prices via Scryfall.
Whenever a nontoken creature you control dies, put a slime counter on this enchantment, then create a green Ooze creature token with "This token's power and toughness are each equal to the number of slime counters on Gutter Grime."