Arm-Mounted Anchor is a rare Artifact — Equipment card from The Lost Caverns of Ixalan Commander (LCC), collector number 99. Current market price: $0.21, TCGplayer market prices via Scryfall.
Equipped creature gets +2/+2 and has menace. Whenever equipped creature deals combat damage to a player, draw two cards. Then discard two cards unless you discard a Pirate card. Equip {2}. This ability costs {2} less to activate if you have one or fewer cards in hand.