What? What did you say?

Nothing

what / that thing (used in place of words you can't remember at the moment.)

(adverbial particle, dismissive, derogatory) emphasizes disgust, contempt, or otherwise negative feelings of the speaker: whatever

whatchamacallit, X

What?, Huh?

anything; whatever one likes

something

any

above all / no matter how you say it / at any rate / after all is said and done