Koma, Cosmos Serpent 
Legendary Creature — Serpent
This spell can't be countered. At the beginning of each upkeep, create a 3/3 blue Serpent creature token named Koma's Coil. Sacrifice another Serpent: Choose one — • Tap target permanent. Its activated abilities can't be activated this turn. • Koma gains indestructible until end of turn.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL