Collect All Pets Rebirth & Factory Guide
Rebirth Cave lets you turn progress into Mythic Stones for permanent upgrades (Cheaper Eggs, damage, luck). Pets and current Pet Score reset; Total Pet Score and bought percent upgrades stay. The Factory opens around 10,000 Total Pet Score for pet-generating machines.
When the cave opens
Look near the lobby Pet Score boards. Unlock is tied to a full normal collection or a high Pet Score (community pages cite about 240–256). If the door is shut, you still need more unique pets — keep hatching and fusing.
What rebirth does
You convert mythical / high-tier pets into Mythic Stones and spend stones on permanent cave upgrades. Current pets and current Pet Score reset. Total Pet Score (leaderboards) and many purchased percent upgrades (damage, drop rate, and similar) stay.
Read the in-game confirmation every time. TwoZoos has added Ascension and other endgame layers; do not assume an old YouTube reset list is still exact.
Upgrades worth buying first
Cheaper Eggs and Even Cheaper Eggs make every hatch cheaper (Common down from 7,500 toward 6,500 then 5,500; Ascended down from 30M toward 25M then 20M). Damage and luck upgrades speed the next rebirth. Buy what shortens the loop you are actually running.
Factory
Inside Rebirth Cave at around 10,000 Total Pet Score. Machines can generate pets of a chosen egg rarity for Gold, auto-equip stronger results, and auto-fuse leftovers. Unlock costs Mythic Stones. Generation speed should stay in line with Gold income so the line never stalls.
Factory is how dedicated players farm shinies and metallics after the map is open. It is not needed to learn the game or to clear Meadow through Jungle.