I have been doing deranged engine archaeology for shits and giggles and it paid off.

Managed to get to the bottom of native physics on actors without using SKSE or anything like that. No HDT, no SMP, no Bullet, no whatever the fuck, just pure native Havok. Got a tail physically simulated at runtime entirely by the game itself.

There's a very good chance this shit will work on consoles without any crutches too, though I haven't tested it in SE yet.