Looking for input on this thing. I've been noticing an unpleasant odor in my bathroom that's gradually been getting worse over the past couple of weeks. Then I started finding these things in my bathtub. Trying to figure out what they are and if they are the cause of the odor or if they are a symptom of the cause of the odor.

At first I thought they were fruit flies, but once I got my camera on them I knew they weren't. Any help would be appreciated.