Riku of Two Reflections is a mythic Legendary Creature — Human Wizard card from Magic Online Promos (PRM), collector number 51536.
Whenever you cast an instant or sorcery spell, you may pay {U}{R}. If you do, copy that spell. You may choose new targets for the copy. Whenever another nontoken creature you control enters, you may pay {G}{U}. If you do, create a token that's a copy of that creature.