Counterspell

Level 3 Abjuration (Sorcerer, Warlock, Wizard)
Casting Time: Template:Reaction, which you take when you see a creature within 60 feet of yourself casting a spell with Verbal, Somatic, or Material components
Range: Template:60 feet
Components: S
Duration: Template:Instantaneous

You attempt to interrupt a creature in the process of casting a spell. The creature makes a Constitution saving throw. On a failed save, the spell dissipates with no effect, and the action, Bonus Action, or Reaction used to cast it is wasted. If that spell was cast with a spell slot, the slot isn't expended.