WoWDB

Successfully interrupting an enemy with Counterspell casts Supernova at their location.

This effect can only occur once every 45 sec.

Supernova:
Pulses arcane energy around the target enemy or ally, dealing [ 30% of Spell Power ] Arcane damage to all enemies within 8 yards, and knocking them upward. A primary enemy target will take 100% increased damage.