Contravene

With the power that nature has given you, you are able to attempt to interrupt a creature in the process of casting a spell. If the spellcaster is using a spell of 3rd level or lower, the spell the opposing force has casted fails and no longer takes effect. If the spell you are trying to cancel is of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. If your roll is successful, the spellcaster's spell dissipates and no longer has any effect. 

If you cast this spell at an equal to or higher level than what the opposing spellcaster has casted their spell at, the spell automatically dissipates with no dice roll necessary.