Alaskan Bull Worm theories; The big one from "Spongebob, Sandy and the Worm" is larger than the one seen in "A place for pets," so this specimen is most likely either a mature adult or an example of deep sea gigantism; It's most likely an invasive species, native to alaskan waters instead of the pacific waters of bikini atoll; Its blunt teeth are meant for crushing the shells of prey such as barnacle monsters like Rrarrg from "The Monster who came to Bikini Bottom"; The fact that they have expressive eyebrows to show complex emotion and their own language, given that the big one says "Ooouuuch." implies that they're highly intelligent, possibly rivaling humans and bikini-bottomites