Monsarger was a biological weapon created by a race of extinct aliens and kept in a blue capsule.These aliens kept their weapon of mass destruction on a comet by the name of Meranie. The aliens then used a few artificial engines to create the illusion of lush forests and pure air to lure other aliens in and eliminate them with Monsarger, thus creating an intergalactic war before being deceased. Monsarger was still kept on the comet when it traveled into the solar system, thus alerting TPC who then sent Super GUTS to investigate the comet in hopes of it being a refuge for mankind in the future. It was there that Asuka and Nakajima met Hanejiro and discovered the complicated mechanisms, still in use, that created the disguise. While Asuka and Nakajima were in that underground chamber, Ryo and Kariya discovers a plain filled with crashed UFOs. Suddenly, it all made sense. This disguise was spotted, and a mechanism released Monsarger. Monsarger then crashed the underground chamber, which traped Asuka. Nakajima, Ryo, and Kariya then returned to the GUTS Eagle and opened fire, but could not even dent the beast. Asuka was hit and was stuck under by a big rock which have even more big rock above it. Asuka dropped his Reflasher and could get to it. Finaly, Asuka, with the help of Hanejiro, who pushed the Reflasher with it's mouth, transformed into Ultraman Dyna. As Dyna fought, he noticed that Hanejiro was pointing to a hologram Monsarger, pointing his weakness, his brain. With that notion, Dyna transformed into Strong Type and jumped into space. As Monsarger looked up, Dyna kicked fiercely downward, and shattered Monsarger's brain case. With his brain demolished, Monsarger fell and burned away. But special mechanisms inside him caused the comet to explode when Monsarger has been defeated, and so, the GUTS Eagle took off, and returned to Earth with Asuka and Hanejiro.