A mechanical beast that caused destruction on Earth while the Alien Bam trapped Takeshi Yamato in the fourth dimension to prevent him transforming into Ultraman 80. Mechagiras was built in a base in the fourth dimension by earthlings held captive there.

After Alien Bam had lured Takeshi into the fourth dimension, Mechagiras appeared at the UGM Radar Base 1 and destroyed it with a missile launched from its nose. When the UGM came to retaliate, the robot teleported to Radar Base 2 and began attacking. However, the Silver Gull Beta came in pursuit from Radar Base 1 and destroyed the robot’s left eye. Mechagiras retreated to the fourth dimension for repairs.

Later, Takeshi snuck into the Alien Bam base and destroyed their control panel, then transformed into Ultraman 80 to fight Mechagiras inside the fourth dimension. Using a barrier that blocked all of 80’s attacks, Mechagiras pressed the advantage, but after it was dragged into our dimension Mechagiras was unable to block 80’s Succium Beam and was destroyed.