Buzzwole did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Buzzwole, known in Japanese as マッシブーン (Masshibūn), is a Bug/Fighting-typePokémon, and one of the seven Ultra Beasts. It is also known as UB-02 Absorption (Japanese: UB02 EXPANSION). It isn't the only Ultra Beast that has the UB-02 serial, as it shares this with Pheromosa.
Buzzwole is a red and black, half-humanoid, half-insectoid creature. It has a ovarian red head, rimmed with a black ring that is adorned with three horns on the back. Its face consists of two black eyeballs with black and red antennae, and a long, light gray proboscis reminiscent to those of mosquitoes. While it has four insectoid legs, they are connected to a more humanoid body, complete with muscular arms and pecs. It has several glowing sac-like muscles placed on its arms, legs and chest, and glowing rings around its abdomen. Its shoulders and elbows are covered with horns as well, and its hands are black with red fingers. On its back are four orange wings.
Buzzwole can absorb energy and cause a chemical reaction between said energy and its own body fluids, in order to swell its body to an almost explosive extent, strengthening itself so much that it is able to pulverize a dump truck in a single punch. Its muscles bulge to such an extent that they are stronger than steel, raising both its Attack and Defense very well. Buzzwole also has the tendency to show off its body by striking a pose at each action. Whether it is trying to boast, threaten, or communicate has yet to be determined.