Arcane Clash

Once a day, when you see another creature casting a spell at you, you can use your reaction to initiate a magic lock, contesting their magic by casting a spell of your own that is 3rd level or lower. When you initiate the magic lock, each spell collides as the opposing casters each try to overpower the other. Both casters make a contesting spell casting ability checks using the spell casting ability for the spell they cast (ie. If you are a wizard casting a cleric spell learned from the magic initiate feat, you must use Wisdom as your spell casting ability for the clash). The first to lose 3 contesting checks is struck by both spells, suffering the effects of both the spells that were cast in the clash.