bug in the litterbox

Question
this morning i was cleaning litter box and there were small brown flying bugs on the waste. they were not there yesterday what are they?

Answer
Gnats and fruit flies tend to be fond of litter and have a very short reproduction/hatching time, so finding them all of a sudden is common.  Empty and clean the entire litter box, cleanse the area where it is kept (I have heard of some luck with using a dilute vinegar solution in this step), and you will hopefully be able to control them spreading.  These sort of bugs love food and can inhabit your kitchen, but they also have a tendency to be found in bathrooms.

I hope this helps.  Have a lovely day.