Egg

Grudge Egg

Listed in the 08-14 in-game index as hatching Cosmo Brat (100%), but no acquisition method exists yet. Watch for a code, event, or future update.

Confirmed in-game. The numbers on this page match the current in-game index.

Unobtainable

Hatch pool (reported odds)

Cosmo Brat — 100%

How to get it

Currently unobtainable — no chicken lays it and no acquisition route is documented.