Apocalypse is an early game expansion for the Magic: The Gathering trading card game. Apocalypse was released back in 2001. As a game expansion, when compared to others, Apocalypse is a small one as it only has 143 cards with a black border.
This game addition has 4 theme decks. Swoop is one of these theme decks and its cards use the color green.
Clearly, this theme deck has enough cards (60) to get you started with playing MTG in no time. In case you're wondering which cards are special, the Mystic Snake and Yavimaya's Embrace are the rare ones in this deck.