Our continuing saga ...
Friday, Katherine goes shopping for the cats. Among other things, she gets a Catzilla sized litterbox, which if you put wheels on it you could use it as a trailer for a garden tractor.
All is well when she arrives. She thinks.
However, she gets up stairs and finds someone missed the litterbox. Probably Emily, since it didn't get buried.
Katherine is cleaning this up when Billy shows up, hops in the other litterbox ... and misses.