School: Abjuration
Casting Time: 1 reaction, which you take when you see a creature within 6 foundations of you casting a spell. This takes place outside the initiative order.
Range: within 6 foundations of you
Components: S, M, (4 White Glowing Gems)
Duration: Instantaneous
Classes: Sorcerer, Warlock, Wizard

Description:
You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell, its spell fails and has no effect. If it is casting a spell of Expert level or higher, make an ability check using your spellcasting ability against the caster’s spellcasting ability. On a success, the creature’s spell fails and any effects incurred from the spell casted may be reversed and the target may restore a number of hitpoints up to the amount of damage taken from the spell.