Riptide Gearhulk is a mythic Artifact Creature — Construct card from Aetherdrift (DFT), collector number 219. Current market price: $2.67 (foil $3.17), TCGplayer market prices via Scryfall.
Double strike Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) When this creature enters, for each opponent, put up to one target nonland permanent that player controls into its owner's library third from the top.