Counterstrike

You attempt to interrupt a creature in the process of casting a spell by destroying the weave around them. Move up to your movement speed towards the caster, and make a melee attack with it against your weapon. On a hit, the target suffers the weapon attack’s normal effects, and the target's spell dissipates with no effect, with the action, Bonus Action, or Reaction used to cast it being wasted. If that spell was cast with a spell slot, the slot isn’t expended.