Breath of Fury and Lord Skitter on the battlefield.
Breath of Fury attached to another creature you control that can attack this turn.
An opponent cannot block creatures you control.
You control a Mountain.
Steps
At the beginning of your combat phase, Lord Skitter's second ability triggers, creating a 1/1 Rat creature token.
When the Rat enters the battlefield, Lord Skitter's first ability triggers, exiling up to one card from an opponent's graveyard.
Deal combat damage to an opponent using the creature with Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature with Breath of Fury attached, then attach Breath of Fury to the Rat token, untap all creatures you control and to get an additional combat phase after this one.