The human-to-Zoanoid transformations, which are always Body Horror.
Sho fighting a doppelganger created from his own arm after his first death. (This was unfortunately cut out of the anime for timing purposes.)
Although they did pay attention to it. When Enzyme rips out Sho's Control Medal, the form he devolves into was obviously based on the monster that grew from his arm in the manga.
The first activation of a Guyver unit is always a horrifying experience.
And in the OVA movie, with the female Guyver, it is.
Sho's father turning into a Guyver-killing Zoanoid while being carried on his back. Combined with a Tear Jerker. It's one of the few times that the Narm of Enzyme's design is averted.
Aptom when he takes over someone's body. shiver
The most frightening example is when he absorbed Elegen, who cried out in terror before Aptom crushed his head, which was still attached to Aptom's body. The 2005 Anime made this scene even more terrifying, as Aptom stretched his arms out from where he was hiding, ensnared Elegen, and dragged him into the dark woods. Elegen's screams can be heard by the surviving members of Hyper Zoanoid Team Five as Aptom assimilated him into his body. Despite the fact that they're evil, it's hard not to feel scared for them.
Each time a Guyver is eaten, manga, OVAs, film or the anime it varies from this or extremely gruesome.
In a more down to earth sense of terror any scene where casualties occur at school. Such as a sniper killing several people in the first animated movie, or Team Five attacking the school in the first OVA.
The process of becoming a Zoanoid while it does give humans enhancements such as a robust healthier body, but it does turn you into a grotesque monster. ** Worse yet it also allows for the removal of free will. Your mind can instantly be shut down, your will removed, and practically become a mindless creature that can do heinous things to innocent people or even the ones you love; such is the ate of Sho's tragic father.
Even worse is the failed Zoanoids or those who never completed their transformation process involves their bodies gradually breaking down and decaying as if suffering from aggressive cancer and multiple organ failure.
The lost numbers are their own horror. They are ostracized from Chronos and are usually doomed to be continually experimented on in agonizing pain for the rest of their existence unless a they are deemed useful for a tasks.
In the Manga, Chronos once managed to grow some of the organism that the Guyver is without it's control medal. The result is akin to the 1982's The Thing, not only can it shapeshift, but it will absorb any and all biological organisms that it touches. Unlike that creature it doesn't seem to gain intelligence, which might explain why the Sho's arm based clone was only single minded in hunting him instead of absorbing all life in it's path.
Apotom functionally is similar to both the Guyver and the Thing after he's body was modified enough by Hamilcar Barcas. Which functionally gives Aptom the same abilities as alien from the Thing, such as genetic memory at a cellular level even when split up into multiple bodies. Unlike the guyver bio booster creature, he is intelligent enough to mimic humans and zoanoids, isolate them, and then eat them alive. Once eaten, Aptom absorbs their abilities and biomass to add to his own. One might be thankfully that his cells can be infected by a virus that counteracts these abilities and keep him in check.
