Not to be confused with Eggsteroids wormholes
Portals also appear in Angry Birds 2, most notably in the Bamboo Forest.
They reappeared at Angry Birds Friends on the 2016 Halloween Tournament as a reference to the game Portal,they made a lot of appearences after the tournament.
In each level with portals, they always come in pairs. Whatever enters a portal in front of the slingshot will exit its corresponding portal facing the pig structure. In the event with two or more portals facing the slingshot, each portal will have a different colored dimensional wall to indicate which portal will lead to.