Elon Musk and Sam Altman used each other's AI to prove themselves right amid a feud, which started after Musk alleged Apple's App Store of favouring ChatGPT. "Good bot," ChatGPT wrote on X as Grok said Musk directed "X algorithm changes to boost his posts". "You too," Musk replied to ChatGPT, sharing its response calling him more trustworthy than Altman.