Team Rocket Returns is a set in the EX series. It was released on November 1, 2004. The printed size is 109. This checklist is longer, at 111 cards. Dark Metal Energy is 94/109, in position 94 of 111 on this checklist. Before it is 93 Venture Bomb, and after it is 95 R Energy. The listed rarity is Uncommon.
Dark Metal Energy is an Energy card. It is listed as Special.
Takumi Akabane illustrated this card. The same name is on 51 other cards in the catalog.
The card text says: Attach Dark Metal Energy to 1 of your Pokémon. While in play, Dark Metal Energy provides Darkness Energy and Metal Energy, but provides only 1 Energy at a time. (Doesn't count as a basic Energy card when not in play and has no effect other than providing Energy.)
I keep a set binder for Team Rocket Returns, meant to hold every card of that set. This card is one slot in the Team Rocket Returns set binder. I still need this card.