been considered a stereotyped character; Sharon Lamb and Lyn Mikel Brown wrote in their 2007 book Packaging Girlhood that Pearl exhibits the traits of an archetypal girly girl. A study by the federal office of gender equality in Mexico, El Instituto Nacional de las Mujeres, found that Pearl's roles sometimes rely on characteristics associated with stereotypes of women, such as vanity and materialism. In an article for Complex, Debbie Encalada praised the SpongeBob series for challenging social norms; the portrayal of the Krabses as a single-parent family was specifically highlighted as an example of the show's "subversiveness by subtly challenging the idea of the nuclear family". Psychologist Steve Harriman covers the Krabs family dynamic in the 2005 Berkley Book Absorbing SpongeBob. He calls attention to the lack of explanation for the disparity between Pearl and Mr. Krabs' species, noting that it is only after watching several episodes that viewers realize the Krabs family is broken. He also questions the decision to focus on Patrick's family, rather than Pearl's, in the only episode dealing "head-on with a core pathology of family"—"I'm with Stupid". In his review of the third season, Bryan Pope of DVD Verdict called Mr. Krabs and Pearl (as well as Krabs' girlfriend Mrs. Puff, whom he mistook for the character's wife) one of "the most head-scratching family units [he had] ever come across". Fan theories The absence of Pearl's mother has caused much speculation among viewers since the series' debut. Various fan theories about how Pearl became Mr. Krabs' daughter have become popular on the internet. Jon Negroni, author of the Pixar theory, theorized that Mr. Krabs' fear of fish hooks in the episode "Hooky" is the result of Pearl's mother being killed by one. Another theory reported by Metro UK proposed that the secret ingredient of Krabby Patties is whale meat from the former Mrs. Krabs. In May 2017, BuzzFeed posted a tongue-in-cheek analysis of how Pearl possibly calls Mr. Krabs "daddy" because he is her sugar daddy and not her father. The article noted that the theory was impossible within the show's universe, but it had seen "a resurgence" of popularity on Twitter, where one post of it received more than 53,000 likes within three days. In other media Pearl has been featured in a variety of merchandise such as plush toys, video games, comics and trading cards. The Krabs family restaurant, the Krusty Krab, has