Text (LG+errata): {3},{Tap}: The next time a source of your choice would deal damage to you this turn, that damage is dealt to target creature of an opponent's choice instead. [Oracle 1999/09/03]
It does not target the opponent, but you still choose an opponent. [WotC Rules Team 1998/02/01]
If you have no creatures, your opponent must still choose a creature even if it ends up being one they control. [Aahz 1994/06/17]
In multi-player games you can choose a different opposing player each time it is used. [Duelist Magazine #4, Page 64]
Extended tournaments (see Rule 913) have always banned this card.