Tradewind Rider | Intruder Alarm | Priest of Urabrask

Cards

Priest of Urabrask in hand.
Tradewind Rider and
Intruder Alarm on the battlefield (
Tradewind Rider without summoning sickness).

Cast
Priest of Urabrask by paying ({2} magic symbol) ({R} magic symbol) .
When
Priest of Urabrask enters the battlefield, it and
Intruder Alarm trigger.
Resolve the
Priest of Urabrask trigger, adding ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Resolve the
Intruder Alarm trigger, untapping all creatures.
Activate
Tradewind Rider by tapping it,
Priest of Urabrask and one other creature you control, returning
Priest of Urabrask from the battlefield to your hand.
Repeat.

If you control creature(s) that can tap to produce mana, you can use that mana to pay for the creature and instead gain mana from the creature's ETB ability.