Aegirocassis, a giant filter-feeding arthropod that lived during the early Ordovician period (around 480 million years ago). It's a relic from the Radiodonta order, which dominated during the preceding Cambrian period.
It was large for its time, measuring nearly 2 meters long, especially since most animals of that era were smaller. It specialized in filter-feeding similar to the modern Baleen whale.
No living creatures from this order exist today.
This is not a detailed illustration; it's just a sketch to capture the feel of Aegirocassis in its environment.