Perkins reprised his Norman Bates role for a cereal commercial in 1990
Pretty funny stuff actually.
https://www.youtube.com/watch?v=c6s5DjcLWUI
Heh, DiGiorno's Psycho Pizza ad. from 2000 doesn't have Perkins but is even better I think (and must have cost quite a lot more to get all the rights to so much Psycho intellectual property including the famous Font/Logo):
https://www.youtube.com/watch?v=osKpR9MjA3E