Does 10 damage plus 20 more damage for each Special Energy card in your opponent's discard pile.
Darkness Chant やみのじゅもん
Count the number of Basic Pokémon or Evolution cards in your discard pile. Put that many damage counters on the Defending Pokémon. You can't put more than 6 damage counters on the Defending Pokémon in this way.
There was initially some confusion as to how Darkness Chant worked, as the wording made it appear that the attack required a choice of either Basic Pokémon cards or Evolution cards. It was later clarified that the attack counted both types of cards, not one or the other.