Over Halloween weekend, Grok Bot users found their weekly usage limits maxed out overnight, with some reporting on X that usage jumped from 50% to 100%. Elon Musk confirmed in a Sunday post that the change was not a glitch: “The cost of serving Grok Bot was unsustainably high relative to revenue.” He has not explained on his main feed how subscribers’ usage limits will be impacted moving forward, even as he continues to promote Grok Bot for consumer use cases like buying gifts for family.

The throttling comes despite Grok Bot being positioned as a success story for the newly public SpaceX. A filing last month said AI now makes up 52% of company income, and SpaceX‘s renamed “Super Intelligence” division turned a profit of $431 million, a rarity in the AI industry. That profit would have been higher if not for $1.2 billion in one-time costs related to the acquisition of Cursor. Musk has previously referred to Grok Bot as having “the fastest growth of a product that I’ve ever seen in my life,” but has not yet shared the full impact of the new usage limits.