Grenzo, Dungeon Warden is a special Legendary Creature — Goblin Rogue card from Time Spiral Remastered (TSR), collector number 378. Current market price: $0.62 (foil $13.75), TCGplayer market prices via Scryfall.
Grenzo enters with X +1/+1 counters on it. {2}: Put the bottom card of your library into your graveyard. If it's a creature card with power less than or equal to Grenzo's power, put it onto the battlefield.