Basalt Golem is a uncommon Artifact Creature — Golem card from Mirage (MIR), collector number 294. Current market price: $0.26, TCGplayer market prices via Scryfall.
This creature can't be blocked by artifact creatures. Whenever this creature becomes blocked by a creature, that creature's controller sacrifices it at end of combat. If the player does, they create a 0/2 colorless Wall artifact creature token with defender.