Arcane Feedback

When another creature casts a spell within range, the caster can use their reaction to cause them to suffer a blast of chaotic arcane energy feedback from their spell.

The target of this spell takes 1d8 damage of a random type. Roll on the damage type table to determine the type of damage they suffer. 

At higher levels: This spell can be upcast using a higher level spell slot, but must always be cast using a spell slot equal to, or lower level than, the spell that it is being cast as a reaction to. When cast using a spell slot above 1st level the damage increases by 1d8 for each additional level of the spell slot used.