Breath of Fury attached to a nontoken creature you control with mana value 3 or less.
You have a creature card in your graveyard with mana value 3 or less.
An opponent cannot block creatures you control.
Steps
Declare Treasury Thrull and the creature with Breath of Fury attached as attackers.
Treasury Thrull triggers, returning a creature card with mana value 3 or less from your graveyard to your hand.
Cast the creature by paying ({0} magic symbol) due to Aluren.
Deal combat damage using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the creature with mana value 3 or less, then causing you to untap all creatures you control and to get an additional combat phase after this one.