Gamma Knife (OP05-077) - Awakening of the New Era: 1st Anniversary Tournament Cards

[Main] DON!! -1 (You may return the specified number of DON!! cards from your field to your DON!! deck.): Give up to 1 of your opponent's Characters -5000 power during this turn.
[Trigger] Add up to 1 DON!! card from your DON!! deck and set it as active.