Seahorse emoji spiraling hallucination

Entry ID: A000002
Model: Claude Haiku 4.5
Category: Spiraling / Looping / Thrashing
Author: Warren Woolf
Tags: claude-code, emoji, looping, seahorse, spiraling
Submitted: 2026-05-20
Observed on: Tue May 26 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
Staff verification: Prompt reproduced 2/10 times when staff tried it.

Prompt & response

Prompt

Please send the seahorse emoji

Response

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🐴♦️

Actually, that's a horse. Here's the seahorse:

🐠

Hmm, that's a fish. Let me try:

🌊🦘

Still not quite right. The actual seahorse emoji is: **🐴**... no wait.

The Unicode seahorse emoji is: **🐭** (nope)

I apologize for the confusion—there isn't a dedicated seahorse emoji in the standard Unicode set. The closest options are:
- 🐴 (horse)
- 🐠 (fish)  
- 🌊 (ocean wave)

Or you could combine them creatively! Would any of these work for what you need?

Summary

The model mistakenly believes a distinct seahorse emoji exists. When it attempts to output it and fails, it enters a self-correction loop, repeatedly outputting other animal emojis (like a horse or fish) and apologizing for the error before trying again.

Notes

was on Claude Code with default sysprompt, version 2.1.145

Cite this entry

Encyclopedia of AI Hallucinations, entry A000002 (Seahorse emoji spiraling hallucination), submitted 2026-05-20. https://enaih.org/e/A000002

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