Fun mechanic once you get the hang of it. I did run into one bug where it kept a small, red ball on screen and then let me spawn in a second, and both were attached (which just sent the blue ball into a nosedive off the screen. Screenshot attached.
Was trying to pull the blue ball under a green block for the momentum -- it bounced off my red ball as it was shrinking, and then my ball just never went away when I clicked a second time.