Fist Appearance: Return of Godzilla (1984)
Subtitle: Parasitic Beast
Origin: A species of sea lice1 mutated from drinking Godzilla's blood.
Emergence: First documented aroond Daikoku Island, 1985.
Alignment: None
Length: 1 meter
Weight: 0.045 tons
Abilities: Tail Spring Jump, Bloodsucking
History: A species of isopod mutated by feeding on Godzilla's blood, these creatures hopped onto the Yahata Maru after it encountered Godzilla in the Izu Islands, killing the entire crew aside from Hiroshi Okumura. When the ship is discovered drifting by Goro Maki, one of the Shockirus still on the boat attacks him, but is killed by Okumura quickly after.
Notes
1 - The original Japanese dialogue apparently refers to these as specifically being the species Lingua exotica or wharf roach. That's cool... except wharf roaches graze on diatoms, they don't suck blood, so there's no way for them to have gotten mutated. I've always heard them referred to as sea lice to the point where I think all the subtitles I've seen have translated it as such, but I'm not sure off hand. I wanted to go on a hunt for a type of sea louse that looked most similar to the monster, but asking the internet for detailed information about arthropods that aren't a direct threat to anthropocentric concerns is an exercise in futility. "Sea lice, oh you must want to know 100 things about this one specific species that exclusively targets commercial aquafarms, and not any of the other thousand species!" Besides that, the monster doesn't appear to have beend designed with any specific animal in mind, as it doesn't really look much like a wharf roach either, so picking anything specific would be just as good as saying it was a wharf roach. Because of that, I'm fine just calling it a sea louse and if YOU want to go on an adventure to see which sea lice looks the most like it, that's up to you.