Any way to script the head of an actor to come off? I want to add this as a perk to horse combat.

Have you tried forcing the decapitation animation to occur? Sometimes when my game bugs out I see the head fly off without the kill move playing, maybe you can get that to happen.

Decap does happen in the vanilla game the first time you get to Solitude. I can't help with scripting, but you may want to look at the workings of that quest. It relates to a Talos worshipper getting the ax just as you enter the city first time.

There's a - decap ability, that you can get using the ability trees. I don't really remember what it is, since I never go there any more....

Looks like this is simpler than I anticipated.

In an On Dying event I am calling the DECAPITATE animation after 4 condition checks to see if the killer was the player and the player is on a horse and sprinting with a melee weapon.

SWEET!

Thank you Elias555, SkyBeth and Serethil very much.