if you adopt a cat as it is leaving or readopt a cat, the cat leaves, wont give you coins but prevents you from getting new cats and leaves you wiht no other cats for a little, sometimes the non adopte cats will also want to play tag wiht nothing
the cats "playing tag" with nothing is actually them chasing your cursor! I think it looks different for people on mobile but if you're on computer, they're chasing your cursor around :D
