The Pathblaster is an enormous Decepticon weapon. In development during the Time Wars, it was being stored on the shuttle used by the Wreckers and the Mayhem Attack Squad. After destroying a chunk of Galvatron's head (a considerable feat, bearing in mind how much the guy had been shot by that time), the gun exploded in Roadbuster's hands. The Pathblaster, Roadbuster, and half of Galvatron's face were never seen again. Although only shown a handful of times, it was this intervention that gave Galvatron the last little step into insanity.