Headcrab Codex Pet

An unofficial, fan-made animated desktop companion for the ChatGPT desktop app and compatible Codex pet surfaces.

The creature is inspired by the late-1990s Half-Life aesthetic: a flattened alien body, four angular legs, a dark underside, restless scuttling, and a classic crouch-and-leap reaction.

Package

• Codex pet spritesheet v2
• Transparent WebP and PNG atlases
• Atlas size: 1536 × 2288
• Grid: 8 × 11
• Cell size: 192 × 208
• Nine standard animation states
• Sixteen cursor-look directions
• spriteVersionNumber: 2

The WebP file is the canonical packaged asset. The PNG is provided for inspection and reuse in compatible tooling.

Install on macOS or Linux

1. Download this repository or the latest release.
2. Create ~/.codex/pets/headcrab/.
3. Copy pet.json and spritesheet.webp into that directory.
4. In the ChatGPT desktop app, open Settings → Pets, refresh the list, and select Headcrab.

~/.codex/pets/headcrab/
├── pet.json
└── spritesheet.webp

Install on Windows

Copy pet.json and spritesheet.webp to:

%USERPROFILE%\.codex\pets\headcrab\

Then refresh the pet list in the ChatGPT desktop app.

Preview states

Idle	Scuttle right	Jump

Additional previews are available in previews/.

Validation

The atlas passed the current hatch-pet v2 structural and visual QA workflow, including transparency checks, all standard state rows, cardinal cursor directions, continuity review, and final contact-sheet review. Machine-readable reports are retained in qa/.

Compatibility note

This repository contains the current local desktop/CLI v2 package (1536 × 2288, 8 × 11). It is not the separate legacy/web-upload 1536 × 1872 atlas format.

Fan-content notice

This is an unofficial, non-commercial fan project. It is not affiliated with, endorsed by, or sponsored by Valve Corporation or OpenAI. Half-Life, Headcrab, and related game characters and marks belong to their respective rights holders.

Do not sell this package or represent it as an official asset. See FAN_CONTENT_NOTICE.md.