Ricochet Trap 

Instant — Trap
If an opponent cast a blue spell this turn, you may pay rather than pay this spell's mana cost.
Change the target of target spell with a single target.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL