Confidence:StrongSolidPlausibleTentativeSpeculative

• Reanimate

  B

  SorceryB

  Reanimate puts Nightsky Mimic onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Helping Hand

  W

  SorceryW

  Helping Hand puts Nightsky Mimic onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Unearth

  B

  SorceryB

  Unearth puts Nightsky Mimic 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 Nightsky Mimic onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Kaya the Inexorable

  3WB

  Legendary Planeswalker — KayaBW

  Kaya the Inexorable bounces a permanent, enabling Nightsky Mimic's recast / spell-cast trigger.
• Shattered Seraph

  4WUB

  Creature — Angel RogueBUW

  Shattered Seraph lets you cast/play from exile, enabling Nightsky Mimic's exile-recursion loop.
• Selenia, Dark Angel

  3WB

  Legendary Creature — Phyrexian AngelBW

  Selenia, Dark Angel bounces a permanent, enabling Nightsky Mimic's recast / spell-cast trigger.