SS Myra
 

SS Myra, by Tom Walker is a webcomic about a sex fiend who put her consciousness into a spaceship and gets her kicks by messing with her crew. Transformations include transgender content, human to robot, human to panties (sort of), mind control (again, sort of), and stuff that defies categorization.

It's a finished comic, not long, you can breeze through the whole archive in maybe a few sittings. But be warned, it's VERY NSFW, and though it's played for laughs it does veer into non-consensual themes.