Over Halloween weekend, some Grok Bot users awoke to something especially spooky: Their weekly usage limits were unexpectedly maxed out, even if they hadn’t been using SpaceX’s agentic AI overnight. Some users reported on X that their usage jumped from as low as 50% to 100%.

SpaceX CEO Elon Musk confirmed in an X post on Sunday that this was not a glitch.

“The cost of serving Grok Bot was unsustainably high relative to revenue,” he wrote in a reply to a question from a user. He has not addressed the issue on his main feed but has continued boasting that Grok Bot can help you buy gifts for your family.

Grok Bot has been positioned as a success story for the newly public SpaceX, which said in a filing last month that AI now makes up 52% of company income. Its renamed “Super Intelligence” division actually turned a profit of $431 million, which is a rarity in the AI industry. Its profit would’ve been higher if not for $1.2 billion of one-time costs related to its acquisition of Cursor. Musk recently referred to Grok Bot as having “the fastest growth of a product that I’ve ever seen in my life.”

Musk has not yet shared how subscribers’ usage limits will be impacted moving forward.