Confidence:StrongSolidPlausibleTentativeSpeculative

• Delney, Streetwise Lookout

  2W

  Legendary Creature — Human ScoutW

  Delney, Streetwise Lookout makes Ouroboroid's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Roaming Throne

  4

  Artifact Creature — GolemC

  Roaming Throne makes Ouroboroid'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 Ouroboroid'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 Ouroboroid's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Reanimate

  B

  SorceryB

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

  2B

  EnchantmentB

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

  1B

  Enchantment — AuraB

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

  1B

  SorceryB

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

  G1B

  Sorcery // SorceryBG

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

  2B

  SorceryB

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

  1B

  SorceryB

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

  BB

  SorceryB

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

  2B

  EnchantmentB

  Necromancy puts Ouroboroid onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Too Evil to Stay Dead

  2B

  SorceryB

  Too Evil to Stay Dead puts Ouroboroid onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Vesperlark

  2W

  Creature — ElementalW

  Vesperlark puts Ouroboroid 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 Ouroboroid 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 Ouroboroid 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 Ouroboroid 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 Ouroboroid onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Reincarnation

  1GG

  InstantG

  Reincarnation puts Ouroboroid onto the battlefield from a graveyard without casting it, so its mana cost is never paid.