This is Joseph Leidy's Biomyxa vagans, was photographed with differently contrast methods (Dark field, Phase, DIC). We found them in an old sphagnum sample from Saxony.
Just great images of an amazing organism. Do you know what the small highly refractile things are in the last image. Some sort of small flagellate prey? Also I don't have a feeling for just how big this beast is, but I get the impression its pretty large?