Flip a coin. If heads, the Defending PokÃ©mon can't retreat. (Benching or evolving that PokÃ©mon ends this effect.)
Poison Bite 20
If this attack damages the Defending PokÃ©mon, the Defending PokÃ©mon is now Poisoned and you remove a number of damage counters from Ariados equal to half that damage (rounded up to the nearest 10). If Ariados has fewer damage counters than that, remove all of them.