Metamagic Option: Blood Spell

You’ve learned how to exert yourself past normal limits and use your own life energy to power your spells.

When you cast a spell that is a 1st level spell or higher, you can spend 1 sorcery point per spell slot and roll 3d6 per sorcery point used. You take the amount rolled minus your Constitution modifier in Necrotic damage (this damage by passes any resistances or immunities; temporary hit points can be used) and can cast the spell without using the spell slot.