No changes in either Kingler's attack stat or Celebi's defence stat, yet the second Knock Off does significantly less damage. I get that attacks have variance in power, but that's only like 1-3%, not 18%. Clearly wasn't a critical hit either. I've never seen this happen before. So why did it?
Effect: Causes the target to drop its held item for the duration of the battle and deals 50% more damage if the target is holding an item, unless the target is holding an item that can change its forme.