This deck revolves around the synergy between Carrion Feeder, Gravecrawler, and Diregraf Colossus. If you have all of these creatures in play, it allows you to pay B to put a +1/+1 counter on Carrion Feeder while also making a Zombie token with Diregraf Colossus. The deck also makes use of some other nice synergies such as Zombie Master and Urborg, Tomb of Yawgmoth to make all of your creatures unblockable. Nameless Inversion is really awesome with both Colossus and Lord of the Undead since it allows for repeatable removal and/or makes a token. It is also an easy way for Diregraf Colossus to enter as a 3/3 on turn 3. Noxious Ghoul allows for repeated Gravecrawlers to destroy your opponents creatures every turn. The only concern is that it might be nice to have an additional free sacrifice outlet other than Carrion Feeder but none of the others seemed as good.
4 Gravecrawler
4 Carrion Feeder
4 Diregraf Colossus
4 Lord of the Undead
3 Zombie Master
1 Relentless Dead
1 Geralf's Messenger
3 Noxious Ghoul
4 Nameless Inversion
4 Victim of Night
4 Hymn to Tourach
Lands (24)
3 Cabal Coffers
3 Urborg, Tomb of Yawgmoth
18 Swamp