Activate Eldrazi Displacer's ability by paying {2}{C}, blinking Brood Monitor.
Brood Monitor enters the battlefield tapped, triggering itself, creating three 1/1 Eldrazi Scion tokens.
Activate three Eldrazi Scions by sacrificing them, adding {C}{C}{C}.
Repeat.

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Eldrazi Displacer

Brood Monitor

Activate Emiel the blessed to flicker Brood Monitor.
Brood monitor's etb effect triggers creating 3 eldrazi scions.
Sacrifice the Eldrazi Scions to activate Emiel the blessed's ability.
Repeat.

Emiel the Blessed

Activate Ashnod's Altar by sacrificing Brood Monitor, adding {C}{C}.
Brood Monitor dies, triggering Nim Deathmantle, causing you to pay {4} to return Brood Monitor from your graveyard to the battlefield, and attach Nim Deathmantle to it.
Brood Monitor enters the battlefield, creating three 1/1 Eldrazi Scion creature tokens.
Activate Ashnod's Altar by sacrificing an Eldrazi Scion, adding {C}{C}.
Repeat.

Infinite colorless mana

Infinite creature tokens

Nim Deathmantle

Ashnod's Altar

Activate Phyrexian Altar by sacrificing Brood Monitor, adding {1}.
Brood Monitor dies, triggering Nim Deathmantle, causing you to pay {4} to return Brood Monitor from your graveyard to the battlefield, and attach Nim Deathmantle to it.
Brood Monitor enters the battlefield, creating three 1/1 Eldrazi Scion creature tokens.
Activate Phyrexian Altar three times by sacrificing three Eldrazi Scions, adding {3}.
Repeat.

Phyrexian Altar

Activate Phyrexian Altar by sacrificing Brood Monitor, adding {W}.
When Brood Monitor dies, Mazzy's second ability and Gift of Immortality trigger.
Resolve the Mazzy trigger, exiling Gift of Immortality with the ability to cast it until end of your next turn.
Resolve the Gift of Immortality trigger, returning Brood Monitor from your graveyard to the battlefield.
When Brood Monitor enters, it triggers, creating three creature tokens.
Activate two creature tokens by sacrificing them, adding {C}{C}.
Cast Gift of Immortality from exile by paying {2}{W}, attaching it to Brood Monitor.
Repeat.

Combos with "Brood Monitor"