My two are like that every time one of them leaves something big in the litterbox. I don't know if it's a kind of, hey, look what I've done, aren't I clever or what but it drives them potty and then the other one joins in. Smashed plates and cups, duvet pounced on and bags ripped and they've been known to run across my head, in their mad game of tag, as I sit on the sofa.
One of them does a damn good impression of crazy frog too!
With regard to their hearing, 'm quite pleased it's so good as they act like two little guard cats everytime someone approaches the front door (sitting there waiting)...and then about 20 seconds later the bell rings! God bless them.