Bladecoil Serpent is a mythic Artifact Creature — Serpent card from The Brothers' War (BRO), collector number 229. Current market price: $0.36 (foil $0.42), TCGplayer market prices via Scryfall.
When this creature enters, for each {U}{U} spent to cast it, draw a card. When this creature enters, for each {B}{B} spent to cast it, each opponent discards a card. When this creature enters, for each {R}{R} spent to cast it, it gets +1/+0 and gains trample and haste until end of turn.