Requires

Ghave, Guru of Spores must be on the battlefield. Cryptic Trilobite must be on the battlefield. Butcher Ghoul must be on the battlefield. Corpse Knight must be on the battlefield. Butcher Ghoul does not have a +1/+1 counter on it. Mana needed:

Steps

1. Activate Ghave's second ability by paying and sacrificing Butcher Ghoul.
2. Butcher Ghoul's undying ability triggers, returning Butcher Ghoul from your graveyard to the battlefield with a +1/+1 counter on it.
3. Butcher Ghoul enters the battlefield triggering Corpse Knight, causing each opponent to lose 1 life.
4. Resolve the Ghave ability, putting a +1/+1 counter on Cryptic Trilobite.
5. Activate Cryptic Trilobite by removing a +1/+1 counter from it, adding that can only be spent to activate abilities.
6. Activate Ghave's first ability by paying and removing a +1/+1 counter from Butcher Ghoul, creating a 1/1 Saproling creature token.
7. The Saproling token enters the battlfield triggering Corpse Knight, causing each opponent to lose 1 life.
8. Repeat.

Results