Harmonize {5}{U} (You may cast this card from your graveyard for its harmonize cost. You may tap a creature you control to reduce that cost by {X}, where X is its power. Then exile this spell.)
Format legality
Standard: Legal
Pioneer: Legal
Modern: Legal
Legacy: Legal
Vintage: Legal
Pauper: Legal
Premodern: Not legal
Tournament decks playing Unending Whisper
Mono-Blue Terror (Pauper, 5.3% of the meta): 1 in the main deck of 1% of lists