Belongs to the Thecamoeba genre
probably it is Thecamoeba sphaeronucleolus
We can see its "heart" (nucleus) and a large vacuole
Thanks Ferry J. Siemensma:
https://www.arcella.nl
for your always generous help
40X objective
Video link:
https://www.youtube.com/watch?v=JG0xTMCq-1Y
Video frame ONLY for preview:

Regards
carlos