Ashiok's Reaper + Mortuary + Phyrexian Altar + Gnarled Scarhide

Ashiok's Reaper

Mortuary

Phyrexian Altar

Gnarled Scarhide

How it works

1. Activate Phyrexian Altar by sacrificing Gnarled Scarhide, adding .
2. When Gnarled Scarhide dies, Mortuary and Ashiok's Reaper trigger.
3. Resolve the Mortuary trigger, putting Gnarled Scarhide on top of your library from your graveyard.
4. Resolve the Ashiok's Render trigger, causing you to draw Gnarled Scarhide from your library.
5. Cast Gnarled Scarhide by paying .
6. Repeat.

This clever loop uses Phyrexian Altar as the engine to sacrifice Gnarled Scarhide for black mana, which conveniently pays the exact {B} cost to recast it. As Gnarled Scarhide heads to the graveyard, Mortuary intercepts the creature card to place it right back on top of your library. Meanwhile, Ashiok's Reaper watches your enchantments hit the graveyard and converts each sacrifice into a brand-new card draw.