Nipponites must have been so great
Nobody has ANY idea how they lived. We just know they were ammonites with ridiculous twisty knots for shells that make no sense.
One theory was even that they couldn’t move, but grew around something else and filtered plankton with their tentacles. Like maybe they grew in this “knot” throughout the body of a sponge or even embedded in rock. There’s a kind of snail that does this today!