Radiolaria is a diverse grouping of amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule of cytoplasm separating the cell into inner and outer cytoplasmic portions, called endoplasm (with nuclei) and ectoplasm (or extracapsulum). As protozoans, radiolarians are tiny, single-celled eukaryotes, and as ameboids they move or feed by temporary projections called pseudopods (false feet). Since there are diverse taxonomic schemes used for protozoans, which span several phyla, the radiolarians are diversely classified as well, ranging from being considered a phylum, to being a subclass of Actinopodea, to not being recognized as a natural taxonomic group.
Haeckel made some exaggerated sketches of them which introduced them to public imagination
I too have been very interested in single celled creatures for a while now.
Foraminifera, radiolarians, rotifers, and larvae of pteropods and bivalves Heterotrophic dinoflagellates, aloricate ciliates, tintinnids, radiolarians, rotifers and copepod nauplii