Infected Bottle?

So last week I bottled my first all grain (an IPA) ad all seems well. After 10 days it looks nice and clear, but while examining a few bottles I came across one that was not like the others. This one has small floating particles at the top, and when i lifted the bottle, some (but only some) began to slowly float down, eventually just kind of free floating somewhere in the middle. I'm about 200 bottles into this homebrewing fun and this is the first time I've had this in a bottle. Obviously I'm not too concerned as this is the exception, but curious as to what to expect.

No expert here, but it could be yeast or krausen forming from the priming sugars.