Text (CH+errata): Choose one - Destroy target red permanent; or return target Mountain to its owner's hand. [Oracle 2003/07/01]
The decision to destroy a permanent or unsummon a Mountain is a decision made on announcement before a target of the proper type is selected. If the spell is redirected, this mode cannot be changed, so only targets of the selected type are valid. [WotC Rules Team 1995/09/22] See Rule G13.13 on Modal spells.
Extended tournaments (see Rule 913) have banned this card since 1999/10/01.
Note - Also see Modal Spells and Abilities, Rule G13.13.
