My cats love to just chase each other around. We have 3 cats but my sister came into town and brought her cat so now we have 4 cats in our house. All they ever do when they want to play is just chase each other or wrestle. its so fun to watch them. when were in the basement and the cats are playing tag, it sounds like thunder... its so weird.
Yeah, I agree that sometimes cats chasing each other above can sound like thunder. When my two chase each other in another room from me it feels like an earthquake!