A fish-like monster that attacks by shooting fire from its mouth.

One rainy night, it was chasing a young boy called Ryo Sakuma, but it was stopped by space investigator Alien Meits and sealed underground with telekinesis.

One year later, Ryo is mistaken for an alien by the townspeople, and Alien Meits is killed by an angry mob whilst trying to protect Ryo.
Freed from the telekinetic seal, Muruchi rises again and begins to rampage.
It delivers a mighty chop to the highway bridge, breaking it in two. Despite the pouring rain, it manages to set ablaze a factory and a tankusing its fire breath.

Ultraman Jack engaged it in powerful hand-to-hand combat, then eventually threw it into a fire and ended it with a Spacium Beam.