You forget, however, his tentacles. He dunked himself in Spring of
Drowned Octopus after his first encounter with Ranma and company. I
can't recall, but it seems that he did a second dunking to himself at
some point as well.

  Tarou splashed his *BACK* with water from that spring.  His back, and
ONLY his back.

  With the fact that "instant spring-of-drowned-man" cured Ranma (albeit
temporarily), it seems to me that the curses DO override each other..
provided that you are COMPLETELY dunked a second time.

  With apologies to Tybalt, I'll shut up now.

mattera@tiac.net
http://www.tiac.net/users/mattera