Ideas for Weasleys' Wizarding Wheezies?

[davewitley]

Amy Z wrote:

> Well, that one sounds cool, except why only for a few seconds?  I 
> guess we already have Polyjuice.  JKR hasn't demonstrated anyone 
> changing genders with it, but you would think if you could lose an 
> eye and acquire completely different physical characteristics for 
an 
> hour, you could change genitals too.

Why so physical?  You could just have a sweet that leaves you - or 
your ex-friend - as a man trapped in a woman's body, or vice versa 
(unless you already were, in which case it would be verse visa, or 
something).

David