How to animate a ball component

Quick question for you animators out there,

How exactly would I animate a ball component? To be more specific, I have a rolling ball game where the ball is the character you play as and he is a ball of goo, a jello-like substance. I would like the mouth that is attached to the ball to open up and shoot out a laser. I made the mouth opening animation in blender where a scalar value determines how far open the mouth is (0 is closed, 1 is open). I would like to have the mouth open up quickly as the player clicks the left mouse button to start shooting his laser and damage enemies.