Fix the adjective error (if one exists).​SpongeBob ​SquarePants ​told ​me ​the ​most excitingest ​story ​about ​his ​trip ​to ​Alaska.

In the sentence provided, the word "excitingest" is an incorrect usage of the adjective "exciting." The correct superlative form of "exciting" is "most exciting."

Corrected Sentence

"SpongeBob SquarePants told me the most exciting story about his trip to Alaska."

Explanation

Adjectives in English can be modified to express different degrees of comparison: the positive form (exciting), the comparative form (more exciting), and the superlative form (most exciting). The term "excitingest" is not standard in English; instead, we typically use "most" before the adjective to form the superlative when it consists of three syllables or more, as in the case of "exciting." Therefore, using "most exciting" maintains grammatical correctness and clarity in the sentence.