Ravaged Plains from SM4 has been revealed! The set will release in Japan on September 15th. Thanks goes to Jake C. for the translation!

Ravaged Plains – Trainer

Stadium

The attacks of each Darkness and Dragon Pokemon in play (both yours and your opponent’s) do 10 more damage to the Defending Pokemon.

This card stays in play when you play it. Discard this card if another Stadium card comes into play. If another card with the same name is in play, you can’t play this card.