Counterlash

You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell is of 3rd level or lower, its spell fails and it has no effect. If it is of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell’s level. On a success, the creature’s spell fails and has no effect. If a spell is countered in this way, you may immediately attempt to cast a spell that you know, at the same level as the spell that was countered.

To do so, make another check using your spellcasting ability. The DC equals 10 + the level of the countered spell. On a success, you may immediately cast a spell at an equal level to the spell that you countered, provided that you have the required components for that spell, and that it can be cast as an action.

"Pathetic, let me show you how it's done"
Ungorath, Dain's mentor.