Hello! I'm working on a humanoid character at the moment and I'm rigging everything to make it do standard actions for a side scrolling game (idle, walk, attack, etc...). I'm trying to implement a fancy animation for when this character (an undead creature) gets slain and I was thinking of making the torso detach from the legs and make these two parts fall on the ground independently.
I've managed to make pieces detach from the main body on other instances by using duplicate bones and alpha but in this case it doesn't seem the best option as the two parts I want to create are fairly complicated and with their own rig, ik, skins, parenting etc...
Is there any method you would suggest instead of duplicating the entire skeleton with the torso/legs parenting removed and using the alpha to switch the rendered skeleton only in that animation?

I was exploring the transform constraint option, but this means that in all other animations I still have to animate the torso and the waist independently as the bones in that section do not of course inherit translation and rotation the same way they would do with standard parenting.

Gamemaker (but I need to check with coder if it's the official one from Yoyo games)

Leaving here a "cheap" solution I found.
I rigged the torso and the legs parenting them separately to two different bones directly parented to the root: one of these bones is at the bottom of the torso while the other is on the waist. I used a transform constraint to link the position of these two bone at 100% mix for translation and rotation. This allows me to animate the skeleton normally as it was in one piece and by turning off the transform constraint (by setting to 0 the mix values during animation) to detach the two above mentioned skeleton sections and animate them independently.
It seems I'm able to achieve most of the animations I was planning to do. If I find any downside while working on this character I'll be sure to update this post for anyone interested.