Sasahiller was an alien who planned to conquer the earth by using his monster Yametaranese to turn all the humans of earth lazy, allowing him to conquer the planet without opposition. As Yametaranese's lazy radiation spread across a city in Japan, Sasahiller watched and goaded all those who were under his monster's influence into falling completely into his plan, even MAT. However once Ultraman Jack managed to partially recover from Yametaranese's Laziness Radiation and send the monster into space where it could live out its days in peace, the alien angrily exited his ship and took matters into his own hands by attacking the city directly. However with Yametaranese no longer within a close vicinity, the lingering radiation affecting Jack's body diminished and with it, Ultraman Jack and MAT were quick to oppose Sasahiller's attack. Ultimately, Sasahiller was no match for the Ultra and was soon reduced into light green foam by Jack's Spacium Beam.