Duskshell Crawler is a common Creature — Insect card from Ravnica: Clue Edition (CLU), collector number 161. Current market price: $0.32, TCGplayer market prices via Scryfall.
When this creature enters, put a +1/+1 counter on target creature. Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)