First off, "animal transformations" aren't really my cup of tea, but hey, why not share whatever one finds if it applies on this forum, am I right?
Anyways, this is from the 1985 Doctor Who adventure "Vengeance on Varos," featuring a prison planet which has evolved into a deranged dystopian government based on gruesome television entertainment.
Its a favourite of mine (HUGE DW fan right here) and chock full of cool stuff, but the only fetish material (unless you are one truly sick individual) comes from a sequence featuring two of the Doctor's female "companions" taken prisoner and sentenced to mutation: one becomes a bird woman, the other a reptillian.
(6:06-6:33, 7:40-8:38, with an explanation of what is happening to them at 9:22-9:51)
AND
(2:27-2:38 for the transformation back to normal)
Not the greatest, but I thought it was worth sharing nonetheless.
P.S. Try not to laugh too hard when you see the Doctor's "clown vomit" coat.