Bring the lion out.
It means to "take out the big guns" or show them their full potential. It also can mean to bring their bravest/strongest team member if in a sport.
Friend 1: We're losing to them 1-2!
Friend 2: Bring the lion out.
Friend 1: She didn't wanna play since her ex was here.
Friend 2: What? Bring the lion out!
Friend 2: Bring the lion out.
Friend 1: She didn't wanna play since her ex was here.
Friend 2: What? Bring the lion out!