Evils of Land Bound to Darkness
Blood magic(Meta Magic) feat from D20. Only difference is It requires 9 hp perm lose to take the feat.
Requirements: 10+ hp, level 3 caster
Ie. You must have a spell slot prepared with feat or do a full round casting for spont caster. When casting the spell after the spell is casted you take 5 damage per level of the spell slot used. Ie 5 for first, 10 for second, 45 for nineth.
Note this is overpowered so I added you lose 9 hp perm.