How to cut down a Skeletal bone socket while Animating in the game

In my case our FPS game have a boss character like Octaman it have 6 Tentacles are play a waving animation.

The Tentacle have 3 part we want the player can shoot the Tentacle and cut down these parts in the Tentacle .

Does Any way can cut down the socket of the skeletal and simulating the physical effect make the cut Tentacle flying away.