What microbe is this?

[Sir]

I typically use an identification chart to help me broadly find out what I'm looking at, but I had no luck with this one.

They were found in a sample of store-bought soil mixed with fertilizer. I mixed it with water, dropped in a few grains of granola and waited about a week. A thick slime formed on top with a bunch of these in it and a whole load of bacteria. In terms of behavior they move pretty quick, and seem to filter water for food at a very fast rate. I really love the way they behave, and had a lot of fun observing them. Anyone know what they are?

Image/video:
1) Still Image
2) Video 1
3) Video 2

[Chris Dee]

Hard to be certain, but looks like Colpodea.

[DonSchaeffer]

I see these all the time in a similar water sample.