After Sun's attempt to assassinate the Fantastic Four with Blastaar failed, Dr. Sun reveals himself at last, trapping the Invisible Woman and the Human Torch within the Baxter Building's security system and besting Mister Fantastic and Thing with H.E.R.B.I.E.'s weapons. He then abandons H.E.R.B.I.E.'s body and transfers his consciousness into the Baxter Building's main computer, which would allow him to control the entire building, and all of the weaponry within. Mister Fantastic is able to lock Dr. Sun away from the rest of the computer system, but H.E.R.B.I.E., now himself again, realizes that Dr. Sun could always simply return to his body. Not wanting the villain to cause any more trouble, the little robot heroically throws himself into the computer, destroying it, Dr. Sun, and himself.