From 2speccers2tools wiki

As their prey became larger and developed many more defenses, it was only a matter of time the local Bruhs would respond by stepping up their own game. This would culminate in the evolution of the Bruhemoth, which is the largest species of bruh to have existed by the time it evolved. It became a distinct taxon since reaching such a large size required the ancestral Terror Bruhs to developed several unique adaptations to support their new lifestyle. The biggest change is the development of a cellular skeleton. This includes two "skull bones" which server as a support for the Bruhemoth's powerful jaws to crush prey since their mouths play just as much of a role in killing and dismembering prey as their nasal appendages. Speaking of which, the three facial appendages have developed more lead-filled spines and the spines being overall larger and the front-most ones even having serrations to help dismember prey faster.

Another big change involves their "fin-skirt" which has become supported by "bony-rods" for them to better apply more force when they beat it back and forth. Because of these structures, however, it swims more like it has four pairs of flippers than it beating a "fin-skirt" which ultimately allows the Bruhemoth to accelerate much more rapidly than any of its ancestors and relatives while improving upon their mobility. Just like their ancestors and close relative, the Bruhemoth will tuck in their prehensile noses to reduce drag. Meanwhile, the photoreceptors still help them track down their large prey, since their large unicellular size means they need to feed on relatively large prey to sustain themselves instead of small microbes.

Unlike their ancestor and close relatives, the Bruhemoth has switched to budding from their rear ends rather than their ancestral binary fission. This is due to their large size meaning relying on binary fission as an active predator can act as a major hindrance. Younger Bruhemoths act somewhat like a large Terror Bruh, but preferring to hunt larger prey rather than microbes to help sustain their more active lifestyle.