Poison Ivy is a playable character in Injustice: Return of the Gods, the sequel to Injustice: Gods Among Us, and was one of the first six characters announced.
Events of Injustice
Ivy kisses her opponent, which causes them to be poisoned. They fall down in agony, so Ivy kicks them in the face and creates several plants to burst out of the ground and attack them.
Ivy's trait allows her to regain her health very quickly.