SpongeBob SquarePants first made a public appearance in 1999, but it took quite some time for the emergence of a scholarly work which directly cited the character as a primary focus for study. This one, from 2005, is a likely candidate as the first :
■ A More Porous Postmodernity: Absurdity, Politics, Consumerism and the Cultural Authority of Spongebob Squarepants
Since then, SpongeBob SquarePants has definitely not been ignored by academia. Here’s a (partial) list of example contributions (in no particular order).
■ Consumption, Health, and Disposability in SpongeBob SquarePants
■ Absurdism in Spongebob Squarepants episode club Spongebob
■ SpongeBob SquarePants: pop culture tsunami or more?
■ An Analysis of Expressive Utterances Produced by the Characters in the Movie Entitiled [sic] Spongebob Squarepants ( A Pragmatic Study)
■ Of Theory and Praxis: SpongeBob SquarePants and Contemporary Constructions of the American Dream
■ Constructing gender and relationships in “SpongeBob SquarePants”: Who lives in a pineapple under the sea?
■ Analysis of Deixis in The SpongeBob SquarePants Movie: a pragmatic approach
■ Social Mores and SpongeBob Squarepants
■ Popular culture and management: the provocation of pongeBob [sic[ SquarePants
BONUS : The ruling of the U.S. Court of Appeals for the Fifth Circuit, 2008, on the case of “The Krusty Krab” (an underwater restaurant in the SpongeBob SquarePants series).