Here's a link to a zombie pod deck that did well in a daily a little while ago that gave me the idea to make this deck http://www.mtggoldfish.com/deck/232686
With Fleshbag, Skinrender, Shriekmaw, and Massacre Wurm there's a removal creature at 3 cmc, 4 cmc, 5 and 6 cmc. Disciple of Bolas can sac a huge Nantuko Husk to draw a ton of cards and Gray Merchant of Asphodel can do a ton of damage with Phyrexian Obliterator and since the deck is mostly all black. Grave Titan is a good finisher and can make a lot of tokens for Nantuko Husk and Blood Artist shenanigans.
You're going to want Misty Rainforest in here. While normally you can budget style a deck this one has Dryad Arbor and Bloodghasts which make the extra land falls very important.
I had fun with a zombie pod deck back when Birthing Pod was in standard. Good times were had with Messenger + Phyrexian Metamorph. To get the max fun out of it, you have to run a full set of them, though, and your deck may not have the room.
I'm sure you get it, but essentially once you get a Geralf's Messenger in play, you can sac it for a Metamorph, copying the now undead (again?) Messenger, which makes the Metamorph a 3cc creature when it's on the battlefield...which you can then sac to Pod for another 4cc Metamorph, etc. When the Messenger/Metamorph come back from undying, it can always come back as something else if needed.
And, if you're already running green, you could easily find room for the Kitchen Finks, Viscera Seer, Melira, Sylvok Outcast combo I think. Infinite Life is good. Viscera Seer might belong in the deck regardless, as it's a great sac outlet and can get you to your Pod more quickly.
http://www.mtggoldfish.com/deck/232686
The idea behind it is to get Gravecrawler, Nantuko Husk, and Blood Artist out to repeatedly sac Gravecaller to gain life and do damage.
I expanded on that idea with this
1 Dryad Arbor
One CMC
4 Birds of Paradise
4 Gravecrawler
Two CMC
3 Blood Artist
3 Bloodghast
Three CMC
2 Geralf's Messenger
2 Nantuko Husk
1 Fleshbag Marauder
2 Phyrexian Obliterator
2 Skinrender
1 Disciple of Bolas
Five CMC
2 Gray Merchant of Asphodel
1 Shriekmaw
Six CMC
1 Massacre Wurm
1 Grave Titan
4 Birthing Pod
3 Abrupt Decay
Lands
4 Verdant Catacombs
4 Overgrown Tomb
4 Woodland Cemetery
8 Swamp
3 Forest
With Fleshbag, Skinrender, Shriekmaw, and Massacre Wurm there's a removal creature at 3 cmc, 4 cmc, 5 and 6 cmc. Disciple of Bolas can sac a huge Nantuko Husk to draw a ton of cards and Gray Merchant of Asphodel can do a ton of damage with Phyrexian Obliterator and since the deck is mostly all black. Grave Titan is a good finisher and can make a lot of tokens for Nantuko Husk and Blood Artist shenanigans.
I'm sure you get it, but essentially once you get a Geralf's Messenger in play, you can sac it for a Metamorph, copying the now undead (again?) Messenger, which makes the Metamorph a 3cc creature when it's on the battlefield...which you can then sac to Pod for another 4cc Metamorph, etc. When the Messenger/Metamorph come back from undying, it can always come back as something else if needed.
And, if you're already running green, you could easily find room for the Kitchen Finks, Viscera Seer, Melira, Sylvok Outcast combo I think. Infinite Life is good. Viscera Seer might belong in the deck regardless, as it's a great sac outlet and can get you to your Pod more quickly.
I'm more of a fan of Restoration Angel + Geralf's Messenger, myself.
No I meant Misty Rainforest. Marshflats are good for getting Bloodghasts, but the Mistys allow you to find your Dryad Arbor.