OpenAI has explained why its ChatGPT models developed an unusual affinity for mentioning goblins and gremlins. The issue stemmed from reinforcement learning in the 'nerdy' personality feature. The company addressed it by retiring the personality and adjusting training processes.
ChatGPT began showing a marked increase in references to goblins and gremlins following the release of GPT-5.1 last November. OpenAI reported that goblin usage rose 175 percent and gremlin usage increased by 52 percent after that launch. The trend intensified with later models like GPT-5.4, prompting an investigation, according to a company blog post published on April 29, 2026, as first reported by sources including Ethan Mollick and CNET coverage of the post. OpenAI noted: “A single 'little goblin' in an answer could be harmless, even charming. Across model generations, though, the habit became hard to miss: the goblins kept multiplying.”
