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The wielder will deal damage to the opponent equal to 1/8 of the opponent's maximum HP if it is hit by a contact move. Stacks with Rocky Helmet. If the wielder is hit multiple times by the same contact move, for example by Tail Slap, then the wielder will deal damage on every hit. If the opponent faints due to Rough Skin damage in the midst of a multi-hit contact move, the move will end. If the opponent uses any of Bug Bite, Circle Throw, Dragon Tail, Pluck, Rapid Spin, SmellingSalt, or Wake-Up Slap, and then immediately faints due to the damage from Rough Skin, then the effect of that move will not take place. The damage dealt is not blocked by Substitute.
This ability, while good, is not seen very much. Garchomp has it, but will only use it because Sand Veil is banned in standard play. Druddigon has two other good abilities to choose from, and Sharpedo always prefers Speed Boost. It would be good if it was found on Pokemon who could take advantage of the ability, but none of the current ones really can.
Found in Dream World