Activate Thermopod's second ability by sacrificing Goblin Arsonist, adding {R}.
When Goblin Arsonist dies, it and Mortuary trigger.
Resolve the Mortuary trigger, putting Goblin Arsonist on top of your library from your graveyard.
Resolve the Goblin Arsonist trigger, dealing 1 damage to an opponent.
Ob Nixilis triggers, putting a +1/+1 counter on itself, and exiling Goblin Arsonist from the top of your library with the ability to play it until your end step.
Cast Goblin Arsonist from exile by paying {R}.
Repeat.

Infinite +1/+1 counters on a creature

Infinite damage

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Infinite storm count

Ob Nixilis, Captive Kingpin

Mortuary

Goblin Arsonist

Thermopod

Activate Phyrexian Altar by sacrificing Goblin Arsonist, adding {R}.
When Goblin Arsonist dies, it and Mortuary trigger.
Resolve the Mortuary trigger, putting Goblin Arsonist on top of your library from your graveyard.
Resolve the Goblin Arsonist trigger, dealing 1 damage to an opponent.
Ob Nixilis triggers, putting a +1/+1 counter on itself, and exiling Goblin Arsonist from the top of your library with the ability to play it until your end step.
Cast Goblin Arsonist from exile by paying {R}.
Repeat.

Phyrexian Altar

Activate Skirk Prospector by sacrificing Goblin Arsonist, adding {R}.
When Goblin Arsonist dies, it and Mortuary trigger.
Resolve the Mortuary trigger, putting Goblin Arsonist on top of your library from your graveyard.
Resolve the Goblin Arsonist trigger, dealing 1 damage to an opponent.
Ob Nixilis triggers, putting a +1/+1 counter on itself, and exiling Goblin Arsonist from the top of your library with the ability to play it until your end step.
Cast Goblin Arsonist from exile by paying {R}.
Repeat.

Skirk Prospector

Cast Goblin Arsonist by paying {R}.
Goblin Arsonist enters the battlefield, triggering Thornbite Staff, attaching it to Goblin Arsonist.
Activate Phyrexian Altar by sacrificing Goblin Arsonist, adding {R}.
Goblin Arsonist dies, triggering itself, Koll, and Thornbite Staff.
Resolve Goblin Arsonist's trigger, dealing 1 damage to any target.
Resolve Koll's trigger, returning Goblin Arsonist from your graveyard to your hand.
Resolve Thornbite Staff's trigger, accomplishing nothing.
Repeat.

Combos with "Goblin Arsonist"