Which Star Trek characters who were main cast in their respective shows haven't been transformed into a species different from their usual one by any means? E.g. alien virus, cosmetic surgery for infiltration, holographic trickery, etc.
I would include Tasha Yar as a transformation because of Sela and the Enterprise-D's reaction to her. I wouldn't include Ethan Philips' first appearance as a Ferengi, but I would when Neelix was made up to look like a Ferengi in False Profits since the first was a separate character and the second was clearly Neelix in disguise. Basically, if the characters who know them best would recognise them as the same character (even mistakenly), they should be included.
I can't remember Dr Crusher or Worf ever being transformed into other species (OK, I just remembered Genesis for Worf), but my memory could be faulty. I would prefer only screen appearances, not comics or books or other appearances.
