Confidence:StrongSolidPlausibleTentativeSpeculative

• Reanimate

  B

  SorceryB

  Reanimate puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Grave Researcher // Reanimate

  2BB

  Creature — Troll Warlock // SorceryB

  Grave Researcher puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Koma, World-Eater

  3GGUU

  Legendary Creature — SerpentGU

  Both cards produce the same kind of effect (shared token subtype).
• Sefris of the Hidden Ways

  WUB

  Legendary Creature — Human WizardBUW

  Sefris of the Hidden Ways puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Recurring Nightmare

  2B

  EnchantmentB

  Recurring Nightmare puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Priest of Fell Rites

  WB

  Creature — Human WarlockBW

  Priest of Fell Rites puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Animate Dead

  1B

  Enchantment — AuraB

  Animate Dead puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Exhume

  1B

  SorceryB

  Exhume puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Life // Death

  G1B

  Sorcery // SorceryBG

  Life puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Dance of the Dead

  1B

  Enchantment — AuraB

  Dance of the Dead puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Victimize

  2B

  SorceryB

  Victimize puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Soul Exchange

  BB

  SorceryB

  Soul Exchange puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Ascent of the Worthy

  1WB

  Enchantment — SagaBW

  Ascent of the Worthy puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Necromancy

  2B

  EnchantmentB

  Necromancy puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Loyal Retainers

  2W

  Creature — Human AdvisorW

  Loyal Retainers puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Karai, Future of the Foot

  1WB

  Legendary Creature — Human NinjaBW

  Karai, Future of the Foot puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• One Last Job

  2W

  SorceryW

  One Last Job puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Rat King, Verminister

  1B

  Legendary Creature — Rat AvatarB

  Rat King, Verminister puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• The Falcon, Airship Restored

  2B

  Legendary Artifact — VehicleB

  The Falcon, Airship Restored puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Reincarnation

  1GG

  InstantG

  Reincarnation puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Pulsemage Advocate

  2W

  Creature — Human ClericW

  Pulsemage Advocate puts Koma, Cosmos Serpent onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Bloodline Recollector // Ancestral Craving

  1BB

  Creature — Vampire Warlock // InstantB

  Koma, Cosmos Serpent is a sacrifice outlet, enabling Bloodline Recollector's death or sacrifice trigger.
• Chevill, Bane of Monsters

  BG

  Legendary Creature — Human RogueBG

  Koma, Cosmos Serpent is a sacrifice outlet, enabling Chevill, Bane of Monsters's death or sacrifice trigger.
• Private Research

  U

  Enchantment — AuraU

  Koma, Cosmos Serpent is a sacrifice outlet, enabling Private Research's death or sacrifice trigger.
• Shaile, Dean of Radiance // Embrose, Dean of Shadow

  1W2BB

  Legendary Creature — Bird Cleric // Legendary Creature — Human WarlockBW

  Koma, Cosmos Serpent is a sacrifice outlet, enabling Shaile, Dean of Radiance's death or sacrifice trigger.