Here's the situation:
My player, a shapeshifted scion of the Amerind deity Raven, is in mortal combat with an NPC wizard. The wizard is on her last legs, realizes she is going to die (the scion was compelled that she didn't know her own strength, the power is new to her), and she casts her death curse. The wizard peers into the scions eyes, initiates a soulgaze, and then funnels herself through the link in an attempt to stuff her own soul into the scion's body. She doesn't have enough power to fully take out the scion, who can go all the way through with an extreme consequence and survive.
So, how would you model this? Right now I'm leaning toward the extreme consequence being an enforced aspect (in particular the player came up with "One Death Curse and She Thinks She's Tricia Helfer" (No. 6 from BSG if you don't get the reference)) and have the wizard partially inhabiting the scion's body, but I gather from reading other posts here in death curse threads that the wizard could make this a spell instead.
For right now I'm interested in gathering opinion, but if you have a specific numerical "how this crap works" to throw at me, go ahead.