Jirass was a giant monster from the original Ultraman series. He is a mutant, frilled-lizard kaiju created by a mad scientist who aspired to create a legend worthy beast. He was killed in a duel with Ultraman.

Ultraman: The Mysterious Dinosaur Base

Jirass was created by a mad scientist as a attempt to remake the Loch Ness Monster, instead he created Jirass. The scientist raised Jirass in Lake Kitayama.

When fish start to disappear from Lake Kitayama the Science Patrol is called in. After finding nothing Ide and his Reporter friend go to meet a the scientist who has extensive knowledge about the lake and monsters. The group is taken hostage by the scientist. When the science patrol try to locate them Jirass arises from the lake, accidentally crushing the scientist. Having no other option Hayata brings out the beta capsule and transforms into Ultraman. After taking a brutal beating at the hands of Jirass Ultraman rips off Jirass' frill causing him to bleed profusely and slowly die. Out of respect Hayata replaces the frill on Jirass neck.

The death of Jirass was sad as the creature was largely an innocent creature unlike most of Hayata's enemies. Jirass caused too much damage to the area likely out of fear and had to be put down.


  • Jirass is a modified Godzilla suit.
  • Jirass is one of the most popular and iconic monsters in the show's long running series, despite only being seen once.
  • The Jirass costume was heavily damaged and repaired before it was used on the show.