Volatile Rig is a rare Artifact Creature — Construct card from Return to Ravnica (RTR), collector number 236. Current market price: $0.25 (foil $0.41), TCGplayer market prices via Scryfall.
Trample This creature attacks each combat if able. Whenever this creature is dealt damage, flip a coin. If you lose the flip, sacrifice this creature. When this creature dies, flip a coin. If you lose the flip, it deals 4 damage to each creature and each player.