The Life Transference spell states:
You sacrifice some of your health to mend another creature’s injuries. You take 4d8 necrotic damage, and one creature of your choice that you can see within range regains a number of hit points equal to twice the necrotic damage you take.
The Twinned Spell Sorcerer Metamagic states:
When you cast a spell that targets only one creature and doesn't have a range of self, you can spend a number of sorcery points equal to the spell's level to target a second creature in range with the same spell.
Life Transference doesn't necessarily target me, nor does it have a range of Self, but it does affect me. Additionally, Twinned Spell does not say that it copies the spell, but that it makes the spell have a second target, and the standard target receives healing based on the damage I take.
So what happens when I try to Twin Life Transference?
- Cast the spell, healing two targets and spend the life cost once?
- Cast the spell, healing two targets and spend the life cost twice?
- Fail to Twin the spell, due to the fact that it affects myself?
Or something else entirely?