Marcellus opens by reflecting on humans’ love of cookies, linking the image to his memory of Tova sweeping crumbs. This sets up his confusion when Dr. Santiago calls him a "smart cookie," a phrase he interprets literally before recognizing it as a human idiom.

During an evening test, Terry lowers a clear, latched puzzle box containing a crab into Marcellus’s tank while Dr. Santiago observes. Marcellus immediately seizes the box, unlatches it, and eats the molting red rock crab in one bite, ending the exercise far faster than expected. Dr. Santiago and Terry frown and argue, disappointed the puzzle did not occupy him longer.

Marcellus then catalogs his abilities: recognizing human faces, discerning tidal shifts by sound, reading fingerprints on the glass, tracking seasonal light patterns, and even learning human letters and words. He emphasizes his tool use and problem-solving, contrasting his capabilities with the other aquarium “prisoners” and noting his distributed neural system.

He accepts being intelligent but resents being trivialized as a snack-like metaphor. The chapter closes with Marcellus asserting his autonomy of thought despite captivity and rejecting the reduction of his identity to a human turn of phrase.