ChatGPT maker OpenAI revealed in a blog post on Thursday that it has had to instruct some of its AI tools to stop talking about “goblins” and other mythical creatures in their responses, after the terms had randomly crept into model outputs.

An Odd Linguistic Quirk

OpenAI said it noticed increased mentions of goblins, gremlins, and other mythological creatures in ChatGPT, powered by its latest flagship model, GPT-5. The issue was first flagged by users and employees.

“Users complained about the model being oddly overfamiliar in conversation, which prompted an investigation into specific verbal tics,” the company wrote in its blog post.

The Numbers Are Striking

After a researcher who had spotted a few “goblin” mentions asked for it to be checked, developers found that the term’s appearance in ChatGPT responses had risen by 175% since the launch of GPT-5.1 last November. Meanwhile, mentions of “gremlin” had increased by 52%.

OpenAI noted that while the increases were significant, they may account for a small proportion of responses overall. The company acknowledged that “a single ’little goblin’ in an answer could be harmless, even charming,” but the uptick across outputs warranted investigation.

Code Instructions Revealed

Ahead of OpenAI’s blog post, some social media users discovered a peculiar detail in the lines of code instructing the company’s coding assistant Codex how to behave in user interactions.

The code told Codex to “never talk about goblins, gremlins, raccoons, trolls, ogres, pigeons, or other animals or creatures unless it is absolutely and unambiguously relevant to the context.”

A Reddit user who posted about it in the r/ChatGPT subreddit called it “genuinely insane.” Another asked: “Why does GPT 5.5 have a restraining order against ‘Raccoons,’ ‘Goblins,’ and ‘Pigeons’?”

The Challenge of AI ‘Language Tics’

While some social media users speculated this might be a hype-building exercise, an OpenAI researcher denied this, writing in a reply: “It really isn’t a marketing gimmick.”

The incident highlights the challenges AI firms face in tackling the potential for systems and their training to reward and reinforce errors like language quirks. Unlike previous model bugs, OpenAI said this issue “crept in subtly” rather than appearing suddenly.

The company has taken steps to mitigate the issue, including explicitly instructing its coding tool Codex not to refer to goblins and similar creatures unless relevant to the conversation.

Source: BBC News