Epic Confrontation

Oracle Text

Target creature you control gets +1/+2 until end of turn. It fights target creature you don't control. (Each deals damage equal to its power to the other.)

Card Rulings

3/16/2018 You can’t cast Epic Confrontation unless you choose both a creature you control and a creature you don’t control as targets.
3/16/2018 If the creature you control is an illegal target as Epic Confrontation tries to resolve, the creature you control won’t get +1/+2. If that creature is a legal target but the creature you don’t control isn’t, your creature will still get +1/+2. In both cases, neither creature will deal or be dealt damage.