Spell Reflection

At 20th level, you add the Counterspell spell to your spellbook, if it is not there already.

When you successfully use Counterspell to counteract a spell that affects targeted creatures or an area, you can turn that spell’s effect back on its caster. When reflected, the spell affects only the original caster, even if it’s an area spell or it would normally affect more than one creature. If an attack roll or saving throw is required, they are made with your spell attack bonus or against your spell save DC respectively.