Declare the creature with Breath of Fury attached and Squirrel Squatters as attackers.
Squirrel Squatters triggers, creating at least one 1/1 Squirrel creature token that is tapped and attacking.
Deal combat damage to an opponent using the creature with Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to a Squirrel token, untap all creatures you control and get an additional combat phase after this one.
Repeat each combat phase.

Infinite combat damage

Infinite combat phases

Infinite creature tokens with haste

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite mana creatures you control can produce

Infinite creature sacrifice triggers

Infinite untap of creatures you control

Breath of Fury

Squirrel Squatters

Urabrask the Hidden

Concordant Crossroads

Anger

Tuktuk Rubblefort

Mass Hysteria

Fervor

Combos with "Squirrel Squatters"