Nihilanth's death animation is actually a Controller's "CONTROLLER_writhing" (but slowed down a bit to make it more realistic).
But what if we put the animation back into Controller?
YEAAAAH! Metal!!!11
Seeing here posts about golden source stuff, I came to show my project, it is about Go-Mod: Reborn, it is the remake of Go-Mod, a sandbox of half-life 1 based on garrys mod
ModDB Page: moddb.com/mods/go-mod-reborn