The bike they are becoming reminds me of a cross between a horse and an insect (and I suppose this symbolism is somehow entangled in cultural signifier for forms of locomotion and transportation (undoubtedly referential in the intent of the original designer's)).

It doesn't matter what the cause of the transformation was; it is too late to reverse it now. Perhaps, it was the creepy cursed garage or some entity with capricious or amoral motives. Nothing can be done at this point to stop it as the body fuses and solidifies and pulls itself into the new form. Someone might luck out later to find a brand new bike, if they themselves don't succumb to a similar fate.

This transformation might be a liberating experience otherwise, if it wasn't into an inanimate object. The mind patterns the computerized components and all organs become machinery, so one becomes a motorcycle through and through. The only senses are those which calculate velocity, motion and internal operations, which provide only a vague impression of traversing space and functioning of a "body" (limited positional region) and are interpreted immediately as control input toward the object's purpose. The existence (if it can be called such) does not resemble human experience at all, and because no semblance remains from which to reverse engineer a human form, the changes are permanent.

I find the idea of inanimate transformation instills an extra degree of horror and the uncanny for "those not experiencing it" as it is an utterly inaccessible existence to the conscious mind, and thus is an absolute other. As an aside, in fiction that depicts this kind of change, my recommendation is to focus on the perspective of an individual who his witnessing the changes to provide a sense of the concrete existence of the individual with only implicit mental changes in the visible behavior (and it's unraveling---the breakdown of subconscious impulses into peculiar and irrational actions---the behavior of the transforming individual would be unusual and uncanny in itself). The elision of body horror and perceptual/philosophical horror of the self can make such a transformation in literature fantastically Kafkaesque (even amplified), but, sadly, it is hardly explored territory.

If the literature focuses on the perspective of the transforming individual becoming an inanimate object, the same technique can be employed in the transforming individual "viewing his or her own self as other"---becoming alienated from his or her own actions, behavior, senses, bodily form, and, at the same time, having the perception of such be unwritten into the alien object itself---viewing oneself becoming an object in the world while one's viewing becomes itself ontological and not phenomenological.

I personally would love to see some more avant-horror, "high" literature depicting inanimate transformations (or peculiar and strange ways to transform, breaking the common archetypes). I am particularly interested in the philosophical issues of decentralizing the self (in the postmodern lexicon) as the root of our psychological unease with our own bodies and why we perceive such transformations as horrific---the wresting of the ego from oneself, even if not a matter of death, but rather of totalized alienation. I would write it, but I don't really feel any impulse to write stories, only language poetry, since I am already spread thin with the various projects I undertake.