Want confuses me about the - oh what it deals damage to itself? Wow that's really not good unless you keep healing it. I guess you could use Max Potion then recover the Double Dragons with those two trainers. I think it's translation is right too most effects that would deal more damage to the opponent's pokemon has a plus sign next to the damage numbers like so: (180+). -and here I thought it might actually have been quite good. Guess Salamence is the better of the two now it has Turbo Blaze Reshiram from Roaring Skies.Mega Garchomp doesn't look that bad...it dies hard to Mewtwo and Gardevoir but with Clawitzer you can power him up pretty quickly, and it wouldn't be too tricky to stream attackers with Puzzle of Time and Special Charge. 180 isn't the absolute best damage but it's pretty decent.
Does the flavour text mean that Garchomp does 10 damage to itself for each damage counter currently on itself?
Well guess it makes getting the Beedrill Mega line now I don't see why they decided it had to deal damage to itself. Would have been neat to have it deal the damage to both itself and the defending Pokemon if they wanted a double-edged sword effect.