A spoiler monster/kaijuu in Shin Godzilla, which made landfall in Kamata, Ōta, Tokyo.
It has amphibian characteristics and a frilled shark-like head. Red fluid is periodically oozing from its gills.
Actually it was the second form of "Larva/Proto-Godzilla" in the story.
It metamorphosed into a bipedal monster ("Monster in Shinagawa") near the Kita-Shinagawa Station.