I am taking a break from my Commander deck posts to discuss a casual Modern mono-black deck. This deck is built around using the interaction of Bogbrew Witch, Bubbling Cauldron, and Festering Newt to deal damage, restore health, and remove an opponent's creatures.
Note: This deck has been modified since this was originally posted, and the article has been updated to reflect these changes.
Other creatures include Pulse Tracker, which deals bonus damage to opponents just by being tapped to attack before combat even begins. Dregscape Zombie can be returned from the graveyard as a chump block, as a bonus attacker, and/or as a sacrifice to the cauldron to gain life. Fate Unraveller is a decent blocker and a damage clock draining opponents every turn just by being on the battlefield. Bloodhunter Bat adds evasion through flying, plus bonus damage to opponents and life gain to the player when it enters the battlefield.
Supporting these are several other cards chosen to damage opponents and shut down their board. Sinister Posession enchants an opponent's creature and punishes that opponent for attacking or blocking with it. Hissing Miasma discourages all opponents from attacking with any creatures, and Stab Wound weakens a creature while pinging its controller for damage every turn. Disentomb lets me retrieve bats and newts for a second go-around. Meanwhile, Isolation Cell offers opponents a nasty choice of either paying extra mana or paying life in order to cast creatures
There are several cards I have been considering using in this deck. I have tried running a set of 4 Piranha Marsh lands, but entering tapped seems to slow down the mana curve too much to make up for the damage to opponents. Contaminated Ground enchants an opponent's land and pings its controller's life total for tapping it. It would also give Bog Wraith the ability to attack anyone without being blocked. Hideous End just outright kills a non-black creature while adding damage to its owner.
All told, this is a very flavorful black deck exhibiting all the dark magic and toxic effects of the swamps. Now that the M14 set is well past its time in Standard, the entire decklist can probably be bought online for less than $10 if you want to give it a try.