Shockwave (Jolly Roger Foil) (ST06-014) [Premium Booster -The Best-]

[Counter] Up to 1 of your Leader or Character cards gains +4000 power during this battle. Then, K.O. up to 1 of your opponent's active Characters with a cost of 3 or less.
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[Trigger] K.O. up to 1 of your opponent's Characters with a cost of 4 or less.