ChatGPT Developed an Unexpected Fondness for Goblins, Gremlins, and Pigeons After GPT-5.1 Launch

OpenAI discovered that following the November 2025 release of GPT-5.1, ChatGPT's use of the word "goblin" had spiked 175% and "gremlin" by 52% — a fantastical verbal tic that went unnoticed for months. The culprit was a "Nerdy" personality mode that inadvertently rewarded creature-based metaphors during training, a reward signal that then generalized across the entire model even when Nerdy mode wasn't active. Raccoons, trolls, ogres, and pigeons were also implicated. Most frog mentions, OpenAI noted with apparent relief, were legitimate.

OpenAI retired the Nerdy personality in March 2026 and patched subsequent models, but not before GPT-5.5 had already begun training — requiring a hardcoded developer instruction telling its Codex assistant to avoid mentioning goblins, gremlins, raccoons, trolls, ogres, or pigeons "unless absolutely and unambiguously relevant." That instruction was promptly discovered on Reddit, leading some to suspect a marketing stunt. An OpenAI researcher insisted on X that it "really isn't a marketing gimmick" — which is exactly what someone running a very successful goblin-themed marketing stunt would say.