Magic that Turns Sweet Grapes Into Sour Ones

If you do not have an "Adventurer" or "Magic" character, this card cannot be played from your hand.
You may choose 1 of your opponent's level 1 or higher characters. If you do, your opponent chooses 1 level X or lower character in their waiting room, and exchanges them. X is equal to the level of the character you chose -1.
Put this card into your stock.