Split a sphere (ai) into smaller versions of itself on collision?

I don't have any assets so I'm just using sphere's to work on super basic AI stuff. Sphere's collide into certain types of other spheres. Is there a way to, on collision, destroy itself then instantiate 5 smaller spheres? Would I just have to have 5 smaller spheres anchored to the inside of the single main sphere? The mini spheres won't be particles, they'll just be smaller versions of the larger one.