If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Flying Whenever you create or sacrifice a token, each opponent loses 1 life.

Spree (Choose one or more additional costs.) + {2}{R} — Untap all creatures you control. If it's your combat phase, there is an additional combat phase after this phase. + {2} — Creatures you control get +1/+0 and gain first strike until end of turn. + {R} — Choose target opponent. Whenever a creature you control deals combat damage to that player this turn, create a tapped Treasure token.