Patrick, Mr. Krabs, Pearl, and Squidward were the first other characters Hillenburg created for the show. Many of their characteristics were based on Hillenburg’s experiences during his time at the Ocean Institute or inspired by the traits of their species. Patrick’s personality embodies the nature of the starfish; according to Hillenburg, they look “dumb and slow” but are “very active and aggressive” in reality, like Patrick. Hillenburg drew inspiration from his former manager at a seafood restaurant while creating Mr. Krabs. According to him, this manager was redheaded, muscular, and a former army cook; these traits were all adapted into Krabs’ character. His decision to design Pearl was influenced by his regular supervision of whale watches at the Ocean Institute, as well as by a cetacean skeleton at the institute. He drew Pearl with an oversized, almost geometric head as a reference to sperm whales having the largest brain size of any extant animal on Earth. He designed Squidward as an octopus because of the species’ bulbous mantle; the octopus, he said, has “such a large bulbous head and Squidward thinks he’s an intellectual, so of course he’s gonna have [one]”. Hillenburg drew Squidward with six tentacles because “it was really just simpler for animation to draw him with six legs instead of eight”.