Perplex

House Dimir Spell
Level 3
Casting Time: Reaction
Duration: Instantaneous
Range: 60 ft
You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect. If it is casting a spell of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 19 + the spell's level. On a success, the creature's spell is still cast, but its Caster must expend another Spell Slot of the kind used to cast the spell in question (or the next highest if no more of that level remain).
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot you used.