This 40 Card theme deck includes a page of guidelines and a foil basic land.

The two things black cards do best are destroy creatures and make your opponents discard cards. The Decay deck does both.

Decay (Black)

16 Swamp

1 Abyssal Specter (Uncommon)

1 Befoul (Uncommon)

2 Blood Pet

1 Bog Imp

1 Corrupt

1 Crypt Rats (Uncommon)

1 Dakmor Lancer (Uncommon)

2 Dark Banishing

2 Drudge Skeletons

1 Duress

1 Fallen Angel (Rare)

1 Foul Imp (Uncommon)

2 Gravedigger

1 Greed (Rare)

1 Looming Shade

1 Mind Rot

1 Ostracize

1 Serpent Warrior

1 Charcoal Diamond (Uncommon)

1 Phyrexian Hulk (Uncommon)