You could set up a system where the cat has to travel though a section on a scale and compare the pre/post weight. Add in a camera to capture photos of the cat on approach and departure (but not during the act) from those motion and weight sensor events.
Put it all together and you could have a bot that posts each trip with the duration and difference between entry and exit weight. There’s probably something useful to learn from those patterns over time (particularly if it shows a sudden change) but mostly I just think it’d be funny if there was an automated system to congratulate a cat for a new personal all-time best or identify their #1 #2 of the week.