If dusknoir lvl X was discarded to the discard pile by the effect of an Attack as in Rhyperior's Deep Scrap does its ability activate that returns it to the owners hand activate or does it remain in the discard pile?
Dusknoir will only return if it was in play as a stadium. If it is sent directly from the deck to the discard pile such as from Deep Scrap, it doesn't return.