Nautilus is a blue creature type that was introduced is only used once, for the card Chambered Nautilus from Mercadian Masques. Originally just a Beast, the creature type Nautilus was added in the Grand Creature Type Update. Much later, Journey into Nyx added Crystalline Nautilus.
The marine nautilus is similar in general form to other cephalopods like squids and octopuses, with a prominent head and tentacles. Thay also have a spiral, chambered shell with pearly septa. This shell can become exquisite jewelry in the hands of Saprazzan artisans.