Razorfield Ripper is a rare Artifact Creature — Equipment Rhino card from Modern Horizons 3 Commander (M3C), collector number 42. Current market price: $0.31, TCGplayer market prices via Scryfall.
Whenever this creature or equipped creature attacks, you get {E} (an energy counter), then it gets +X/+X until end of turn, where X is the amount of {E} you have. Reconfigure—Pay {2} or {E}{E}{E}. (Pay {2} or {E}{E}{E}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)