'll admit, this deck isn't actually based around Black Cat, but it really does play one, and I assume it's a critical part of the plan. It's pretty funny that Black Cat would be a better Magic card if it cost one mana, but that would make it way worse for the purposes of this deck. As it turns out, a casting cost of two is exactly what this deck is looking for, and the reason for that is the powerful and underplayed Immortal Servitude.
All this deck is trying to do (besides enable Black Cat recursion) is fill its graveyard full of two-mana creatures, most of which cycle, and cast a chain of Immortal Servitudes. Each Servitude draws a couple cards, and add a Blood Artist or two into the mix and opponents will quickly burn through all nine of their lives.
Grisly Salvage and Forbidden Alchemy help stock up the graveyard, and each also digs for critical pieces of the combo. Snapcaster Mage is what ties everything together, as he acts as copies of Immortal Servitude 5–8, and is something you can select off Grisly Salvage. Given ten mana, you can even go off with Servitude, return Snapcaster, Servitude, although I wouldn't expect that to be a common occurrence.
Rounding out the deck are a few removal spells to keep you alive, and some Bloodthrone Vampires to make sure all your creatures head to the graveyard when appropriate. The sideboard provides more disruption, with every card being a reactive card of some sort.
vcravalanche's Immortal Servitude
Standard – 3–1, Magic Online Daily Event
Luis Scott-Vargas plays, writes, and makes videos about Magic. He has played on the Pro Tour for almost a decade, and between that and producing content for ChannelFireball, often has his hands full (of cards).