Truthfully I lied that fantasy resurfaced 1 year ago do to science.
(following not possible with modern tech)
theoretically speaking. IT would be possible to genetically engineer a virus to mutate the DNA in human cells so that they exhibit traits of other cells with the right genetic combo you can cause a persons skeletal system to change completely and many other physical things could be changed the same way. but with modern tech even none existent tech it isn’t possible. for 2 reason one it would require injecting the virus into the heart, bones, and brain stem. and 2 it would be ethically wrong. also the fact that I came up with it.