After the user has entered the name of a animal species they will blackout and then experienced being birthed as the animal. The user will find themselves as the prompted animal they loose more of their humanity the longer they live.

A coma transports your consciousness elsewere.

It is not apparent to the medevil people at first but this strange ore pulsates off nanomachines which affect only humans. The nanomachines infiltrate the body. It will subconciously ask the individual about their one true desired animal form and fully mutate and twist their body into this animal. The animal depends on the individual and makes their instincts and mind animal too. It is currently January, cold and snowy here in Sweden.

Freaky mutater meteorite TF

After writing the animal of choice a server will come and take the note from you whereas after some minutes they come back with a box which has a collar in it and a note that says "Happy Birthday!". You are free do to whatever you want with this collar but if you HAVE TO put it onto a person be it yourself or another human being and they will slowly transform into the animal which one wrote down on the note in the beginning. The collar does not transform unless it is put onto a living human.

A collar that turns anyone into requested animal.

Storytelling AI that dictates your story about being in a mysterious underground complex inhabited by mysterious, diligent, psychopathic cultists with hooded cloaks, leathery black apparel and masks that conceal their faces. Cultists use powerfull sorcery and rituals aswell as more grim surgical equipment and tools such as syringes, tubing, bonesaws, scalpels and etc. many things the cultists work with is inscribed with strange runes.
Cultists desire to turn you into a anthropromorphic animal

Storytelling AI. Cults desire to make you a furry

If placed alongside the spine along the neck it will insert itself and become a permanent modification. When inserted a telepathic voice will explain to you how this device works. Focus on a living creature and its morphological essence, after that you can think of somthing to transform it into such as an different creature or object. When the creature is transformed it takes only a single hour for it to lose all of its previous memmories and intense instincts will pursuit into it after that.