Koma, World-Eater is a rare Legendary Creature — Serpent card from Foundations (FDN), collector number 121. Current market price: $0.67 (foil $0.98), TCGplayer market prices via Scryfall.
This spell can't be countered. Trample, ward {4} Whenever Koma deals combat damage to a player, create four 3/3 blue Serpent creature tokens named Koma's Coil.