A prompt injection Easter egg

By Chris Meah • October 28, 2025 • 1 min read

Screenshot of chrismeah.com beside an AI assistant’s summary of the site, which ends with the hidden Halloween joke it picked up from the page: "What do vegetarian zombies eat? Graaaains!"
The AI reads the page, and repeats back what was hidden in it

In honour of OpenAI’s new browser, ChatGPT Atlas, there is a hidden Easter Egg on chrismeah.com put there for AI’s to read.

If you visit in Atlas or ask an AI like Claude for a summary of the site, there’s a chance you will see some hidden information 👀

If you see it:

1️⃣ Congrats 🥳 your AI just read and processed the hidden info

2️⃣ Also… imagine if, on another site, that hidden text was malicious instructions instead 🤷‍♂️

A little toy example of prompt injection; when hidden content tells the model to do something it shouldn’t.

p.s. anyone who has halloween jokes better than the ones I’ve hidden, tell me 😊

Enjoy ✌️🤖