Activate Ashnod's Altar by sacrificing Darksteel Splicer, adding {C}{C}.
When Darksteel Splicer dies, Nim Deathmantle triggers, causing you to pay {4} to return Darksteel Splicer from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Darksteel Splicer enters the battlefield, it triggers, creating at least one 3/3 Phyrexian Golem artifact creature token.
Activate Ashnod's Altar by sacrificing a Phyrexian Golem, adding {C}{C}.
Repeat.
If you have two or more opponents, this combo nets infinite creature tokens and colorless mana.

Infinite colorless mana

Infinite creature tokens

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Nim Deathmantle

Ashnod's Altar

Darksteel Splicer

Activate Phyrexian Altar by sacrificing Darksteel Splicer, adding {1}.
When Darksteel Splicer dies, Nim Deathmantle triggers, causing you to pay {4} to return Darksteel Splicer from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Darksteel Splicer enters the battlefield, it triggers, creating at least one 3/3 Phyrexian Golem artifact creature token.
Activate Phyrexian Altar three times by sacrificing three Phyrexian Golems, adding {3}.
Repeat.
If you have four or more opponents, this combo nets infinite creature tokens and colored mana.

Phyrexian Altar

Activate Thermopod's second ability by sacrificing Darksteel Splicer, adding {R}.
When Darksteel Splicer dies, Nim Deathmantle triggers, causing you to pay {4} to return Darksteel Splicer from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Darksteel Splicer enters the battlefield, it triggers, creating at least one 3/3 Phyrexian Golem artifact creature token.
Activate Thermopod's second ability three times by sacrificing three Phyrexian Golems, adding {R}{R}{R}.
Repeat.
If you have four or more opponents, this combo nets infinite creature tokens and red mana.

Combos with "Darksteel Splicer"