Cast Circle of the Land Druid from your graveyard for its retrace cost by paying {1}{G} and discarding a land card.
Insidious Roots triggers, creating a creature token.
When Circle of the Land Druid enters the battlefield, its first ability triggers, causing you to mill four cards.
Activate Phyrexian Altar twice by sacrificing the creature token and Circle of the Land Druid, adding {1}{G}.
When Circle of the Land Druid dies, its second ability triggers, returning a land card from your graveyard to your hand.
Insidious Roots triggers, creating a creature token.
Repeat.

Infinite creature LTB

Infinite creature ETB

Infinite creature sacrifice triggers

Infinite death triggers

Infinite self-mill

Infinite storm count

Infinite self-discard triggers

Phyrexian Altar

Circle of the Land Druid

Insidious Roots

Activate Phyrexian Altar by sacrificing Circle of the Land Druid, adding {1}.
When Circle of the Land Druid dies, its second ability, Pitiless Plunderer and Pitiless Plunderer trigger.
Resolve the Pitiless Plunderer trigger, creating a creature token.
Resolve the Circle of the Land Druid trigger, returning Takenuma from your graveyard to your hand.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Activate Phyrexian Altar by sacrificing the creature token, adding {1}
When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
Activate the Treasures by tapping and sacrificing them, adding {B}{G}.
Activate Takenuma's channel ability by paying at most {3}{B}, returning Circle of the Land Druid from your graveyard to your hand.
Cast Circle of the Land Druid by paying {1}{G}.
When Circle of the Land Druid enters, its first ability triggers, allowing you to mill four cards.
Repeat.

Infinite colored mana

Takenuma, Abandoned Mire

Pitiless Plunderer

Cast Circle of the Land Druid from your graveyard for its retrace cost by paying {G} and discarding a land card.
When Circle of the Land Druid enters the battlefield, its first ability triggers, allowing you to mill four cards.
Activate Phyrexian Altar by sacrificing Circle of the Land Druid, adding {G}.
When Circle of the Land Druid dies, its second ability triggers, returning a land card from your graveyard to your hand.
Repeat.

Emerald Medallion

Cast Circle of the Land Druid from your graveyard for its retrace cost by paying {1}{G} and discarding a land card.
When Circle of the Land Druid enters the battlefield, its first ability and Genesis Chamber trigger.
Resolve the Circle of the Land Druid trigger, allowing you to mill four cards.
Resolve the Genesis Chamber trigger, creating a 1/1 Myr artifact creature token.
Activate Phyrexian Altar twice by sacrificing Circle of the Land Druid and the Myr, adding {1}{G}.
When Circle of the Land Druid dies, its second ability triggers, returning a land card from your graveyard to your hand.
Repeat.

Combos with "Circle of the Land Druid"