EastScape Wikibuilt from the game itself
Gilded egg
“Put it in a hatchery on your island with 3 Ordinary pet food: a Mimic in 120 hours. Tradable.”
Hatches
Hatches into 
Mimic in your island's hatchery, in 120 hours. It drops from monsters in The Vault, The Trailer Park, The Deep Wild, The Depths of the Mountain.
Sold by
Nestor the Egg Man in The Yard trades it for 30 red house chip + 5 black house chip.
The Store: 960,000 tickets.