Another very old one. In "
Otaku no Video", a somewhat documentary-
themed anime about otaku culture, the main characters create their own
magical girl anime series with AP transformation aspect. The magical girl
character's name is
"Misty May". She is usually a very shy school girl
who's bullied by her schoolmates, but when she transforms, she becomes an
older, confident, and busty magical super idol bunny girl. She has a
transformation sequence, and it has a somewhat funnily animated BE
process.
(5:31-5:45, 6:52-7:11)
https://www.youtube.com/watch?v=fmJKatSCT08
Her transformation in HQ webm format:
https://cs.sankakucomplex.com/data/4...e.webm?4975576