Navanax inermis, common name the California aglaja, is a large species of predatory sea slug, a marine opisthobranch gastropod mollusk in the family Aglajidae.

Navanax is not a nudibranch, even though it somewhat resembles one; it belongs to a more ancient lineage of opisthobranchs called the cephalaspideans or head shield slugs and snails.

[2] Common prey items include other sea slugs, like bubble snails and nudibranchs, and small fish.

[4][5] As N. inermis lacks visual perception, it finds prey by using its chemoreceptors to follow the slime trails of other organisms.

[6] In the southern portion of its range, N. inermis spawns year round, producing upwards of 800,000 eggs at a time.