Hair Transformation

[frice2000]

You might enjoy Ranma season 5 episode 2.

2: 'When a Guy's Pride and Joy Is Gone'

Once it's revealed that the Dragon's Whisker is in fact a powerful hair-growth artefact (and further that, without it, Ranma's hair will grow uncontrollably until he exhausts his life's supply), not only the four niku-men but also chrome-dome Happosai and Genma are out to get their hands on it. Of course, in the Ranma universe everyone eventually gets what's coming to them.

--From http://www.dvdtimes.co.uk/content.php?contentid=6625

That was one I thought of off the top of my head...