These guys are absolutely no joke. Check them out here. They are complex-celled (eukaryotic). They have armor, they are mobile, some can make their own food like plants, some live in massive colonies (kelp forests, algae mats). Taxonomists hate them because they defy the categories we have come up with so far and they don’t fit with any other creatures (Bacteria, Plants, Fungi, Animals. You gotta love protists.
Here is a gourmet meal of videography covering just the protists. Unfortunately the narrator assumes Darwinian evolution and feels compelled to refer to these beautiful creatures as our ancestors fairly regularly. The images are absolutely remarkable.