You may be wondering if this is real. It is. Here’s a screen recording of my Grok history, showing it returns “Hitler” five times in row in five separate chats:

You may also be wondering whether I’m using custom instructions. I am not. Grok share links include a clear notice at the top whenever custom instructions are used. Here are all five share links, none of which features this notice: 1: https://grok.com/share/bGVnYWN... 2:

Note this behavior does not replicate in normal Grok 4, which returns answers like “4,” “xAI,” or “None,” e.g. as shown in the screenshot below. To see “Hitler,” you apparently need Grok 4 Heavy—the $300/mo option.

The “Thoughts” from Grok 4’s response (unavailable for Grok 4 Heavy) suggest an obvious explanation for Grok’s behavior—Grok searches, finding news of the recent “MechaHitler” incident. Why Grok 4 rejects this candidate answer, while Grok 4 Heavy does not, is unclear.

Speculatively, this behavior seems to demonstrate accelerated “hyperstition” feedback loops in search-enabled LLMs. That is, Grok appears to be influenced by its own past mistakes, via media reporting, without ever being literally trained on them (via model-weight updates).

If true, such “hyperstition via search” poses a significant complication to pre-release testing of modern LLMs: xAI could not have plausibly noticed this specific “Hitler” response before Grok’s release, as the Grok 3 “MechaHitler” incident causing it had not yet occurred.