Futurist Spellthief 
Creature — Moonfolk Wizard
Flash When Futurist Spellthief enters the battlefield, conjure a duplicate of target spell into your hand. That card perpetually gains "You may spend mana as though it were mana of any color to cast this spell."
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL