Cast Wormfang Newt by paying {1}{U}.
When Wormfang Newt enters the battlefield, its first ability triggers, exiling Wormfang Newt.
When Wormfang Newt leaves the battlefield, its second ability triggers, returning itself from exile to the battlefield.
Repeat from step 2.

Infinite ETB

Infinite landfall triggers

Infinite LTB

Ashaya, Soul of the Wild

Wormfang Newt

Activate Phyrexian Altar by sacrificing Wormfang Newt, adding one mana of any color.
When Wormfang Newt dies, its second ability triggers, returning a Plains from exile to the battlefield.
When the Plains enters the battlefield, Emeria Shepherd triggers.
Holding priority, activate the Plains by tapping it, adding {W}.
Resolve the Emeria Shepherd trigger, returning Wormfang Newt from your graveyard to the battlefield.
When Wormfang Newt enters the battlefield, its first ability triggers, exiling a Plains.
Repeat.

Combos with "Wormfang Newt"