Cast Mogg War Marshal, creating a 1/1 Goblin when it enters the battlefield.
Sacrifice Mogg War Marshal to the Skirk Prospector, generating {R}, triggering Decaying Soil's ability, and creating another 1/1 Goblin.
Use the {R} to pay for Decaying Soil's ability to return Mogg War Marshal to hand.
Sacrifice the 2 Goblin tokens to Skirk Prospector to generate {R}{R} to recast Mogg War Marshal.
Repeat.

Infinite death triggers

Infinite ETB

Infinite LTB

Mogg War Marshal

Skirk Prospector

Decaying Soil

Cast Mogg War Marshal by paying {1}{R}.
Mogg War Marshal enters the battlefield, triggering itself and Obsidian Battle-Axe.
Resolve Obsidian Battle-Axe's trigger, attaching it to Mogg War Marshal.
Resolve Mogg War Marshal's trigger, creating a 1/1 Goblin creature token.
Activate Phyrexian Altar twice by sacrificing the Goblin token and Mogg War Marshall, adding {R}{R}.
Mogg War Marshall dies, triggering itself and Koll.
Resolve Mogg War Marshal's trigger, creating another 1/1 Goblin creature token.
Resolve Koll's trigger, returning Mogg War Marshal from your graveyard to your hand.
Repeat.
Once you have infinite creature tokens, you may activate Phyrexian Altar any number of times to add infinite mana.

Combos with "Mogg War Marshal"