Counter-Counterspell

"I cast counterspell"

"I CAST COUNTER-COUNTERSPELL"

"WELL I CAST COUNTER-COUNTER-COUNTERSPELL"

- Audio footage from the Second Great Wizard War (1457 DR)

You attempt to interrupt a creature in the process of casting counterspell. The creature makes a Constitution saving throw. On a failed save, the spell dissipates with no effect, and the Reaction used to cast it is wasted. If that spell was cast with a spell slot, the slot isn’t expended. You then create a 15-ft radius sphere around yourself until the start of your next turn, where no one can cast or be affected by counterspell's cast with spell level below 10th.