"Run Iris Run" IRIS SUITS UP Team Flash confronts a new bus meta, Matthew AKA Melting Pot (guest star Leonardo Nam), with the ability to swap peoples DNA. During a battle with Team Flash, Matthew transfers Barrys (Grant Gustin) super speed to Iris (Candice Patton). Now, with a new threat unleashed on Central City, Barry must act as the team leader while Iris takes on the mantle of superhero speedster in order to defeat their new foe. Harry Jierjian directed the episode written by Eric Wallace (#416). Original air date 3/13/2018.