Geronimon, also known as the Monster Chief, was a villanous daikaiju from the original Ultraman series.
One day Geronimon rises in Japan and resurrects three monsters, Dorako, Telesodon and the smaller but friendlier Pigmon. Whilst Pigmon ran off into a nearby toy shop the two monsters Dorako and Telesodon start to fight in the mountains. The science patrol receives a message that said that he was going to resurrect sixty monsters if Ultraman did not show up. Later the science patrol find Pigmon who tells them Geronimon's threat, so the science patrol, and pigmon travel to the mountains, were the group splits up. One group fights Telesodon which is slain by Ultraman, whilst the other fights Dorako who kills Pigmon, but is then disintergrated by ide's new weapon. Finally they rejoin and finally battle Geronimon. At first the battle was in Geronimon's favor, using his special mind controlled razor feathers to cut and slice Ultraman. Ultraman managed to destroy most of them then jumped on Geronimon and ripped off his head dress, then was killed by ide's weapon, thus ending the Monster Chief's reign of terror.