Three-headed ogre that died and split into the strongman brothers, and now exists twice over.
Carl explains that Herman the Fleet, Areson the Wise, and Apollon were all once part of a single three-headed ogre called a nodling, which died and split long ago into three separate strongmen who joined Grimaldi's circus. The same nodling was also turned into one of Carl's monster tattoos, and that tattoo has since been given flesh and should be somewhere around the Princess Posse's holdings too.
The result is two versions of the same creature walking around at once — a duplication Carl finds genuinely disturbing, comparing it to the Alpha Carl card from the previous floor and admitting it messes with your head. He is glad they left the Alpha Carl card behind.
A single ogre body crowned with three heads, each of which became a separate strongman after its death.
Origin creature of the ogre strongman brothers and an unsettling example of dungeon duplication.
Also appears in books you've already read — spoiler-safe to their endings: