Confidence:StrongSolidPlausibleTentativeSpeculative

• Roaming Throne

  4

  Artifact Creature — GolemC

  Roaming Throne makes Leviathan's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Mirror Room // Fractured Realm

  2U5UU

  Enchantment — Room // Enchantment — RoomU

  Mirror Room makes Leviathan's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Wizard's Staff

  1U

  Artifact — EquipmentU

  Wizard's Staff makes Leviathan's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Priest of Fell Rites

  WB

  Creature — Human WarlockBW

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

  1B

  Enchantment — AuraB

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

  1B

  SorceryB

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

  G1B

  Sorcery // SorceryBG

  Life puts Leviathan 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 Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Persist

  1B

  SorceryB

  Persist puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Soul Exchange

  BB

  SorceryB

  Soul Exchange puts Leviathan 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 Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Sheoldred, Whispering One

  5BB

  Legendary Creature — Phyrexian PraetorB

  Sheoldred, Whispering One puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Virtue of Persistence // Locthwain Scorn

  5BB1B

  Enchantment // Sorcery — AdventureB

  Virtue of Persistence puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Reanimate

  B

  SorceryB

  Reanimate puts Leviathan 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 Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Liliana, Death's Majesty

  3BB

  Legendary Planeswalker — LilianaB

  Liliana, Death's Majesty puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Yore-Tiller Nephilim

  WUBR

  Creature — NephilimBRUW

  Yore-Tiller Nephilim puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Sefris of the Hidden Ways

  WUB

  Legendary Creature — Human WizardBUW

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

  2B

  EnchantmentB

  Recurring Nightmare puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Unfinished Business

  3WW

  SorceryW

  Unfinished Business puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Forum Necroscribe

  5B

  Creature — Troll WarlockB

  Forum Necroscribe puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Kroxa and Kunoros

  3RWB

  Legendary Creature — Elder Giant DogBRW

  Kroxa and Kunoros puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• The Cruelty of Gix

  3BB

  Enchantment — SagaB

  The Cruelty of Gix puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Death Is Irrelevant

  6BB

  EnchantmentB

  Death Is Irrelevant puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Liliana, Waker of the Dead

  2BB

  Legendary Planeswalker — LilianaB

  Liliana, Waker of the Dead puts Leviathan onto the battlefield from a graveyard without casting it, so its mana cost is never paid.