This was a lucky catch. The video begins with some large predatory ciliate having captured some smaller ciliate, apparently preparing to eat it. In the first 15 seconds of the video, a second large ciliate intercepts the first one and wrestles away the prey. At about 0:20 and continuing through 0:45, the large ciliate successfully ingests the prey, losing its membranous front end and assuming a fat oval shape with no projections. At that same time, the first predator leaves the scene, apparently figuring there's no longer any chance of a meal here. Processing of the prey and resumption of more normal shape continues through 1:00 (5 minutes of observation). From there through the end of the video (2:18, another 6 minutes real time), the predator gradually finishes processing its meal, regains its normal structure, and starts sniffing around for something else to eat.
Shot with a 20X objective, cropped and scaled in post-processing to about 0.53 mm field width. Each of the panels shown below is about 140x160 microns.
If anybody has an ID for the participants in this little eco-drama, I will appreciate knowing.
Hope you find this interesting!
--Rik
