The fireShotGunSpheres() function generates 20 spheres and adds them to the scene. The sphere's position is set relative to the camera's position, so that the spheres appear always in front of the camera. Each sphere has a SphereGeometry of 0.05 units and a MeshBasicMaterial of yellow color. The spheres are added to an array called shotGunSpheres.
This code can be modified to suit the desired look for the shotgun blast effect. For example, the size and number of spheres, the distance the spheres move, and the color of the spheres can be changed to achieve a different look.