Card: Chord of Calling
Casting Cost: XGGG
Color: Red
Type: Instant
Rules Text: Convoke (Each creature you tap while casting this spell reduces its cost by {1} or by one mana of that creature's color.) Search your library for a creature card with converted mana cost X or less and put it onto the battlefield. Then shuffle your library.

SetRarity
Ravnica: City of GuildsRare