B2 grapple droid

The grapple droid, based on the B2 super battle droid model, was a droid model specifically designed for the Separatists' attack on Coruscant.

Overview
Bigger and profoundly more vicious than its predecessors, the grapple droid was equipped with electrically charged industrial pincers, which it used to crush or impale its enemies. They could also be used to smash through stone walls. The grapple droid excelled at close-quarters combat and its embrace was quite deadly. They proved dangerously efficient against Jedi, who, if grappled, were unable to use a lightsaber.

General Grievous himself personally oversaw its modifications.