Why did I see random maggots in my restroom?

So for context, I moved into a new home and about 15 days later, I wake up early in the morning to use my restroom and see the floor surrounded by around 20 thick maggots. It was on the countertop, on my closet flush button, in my water bucket and on the floor. Thing is I clean my restroom every 2 days and deep clean it every week so I don’t know why this happened. I live in a high rise apartment so this isn’t ground level. After I cleared everything, it didn’t happen again. I still have no clue why that happened. What do you guys think?