In the realm of Poseidon is a beach and what should be a sea, but resembles a lake. The maze and the Hydra cave are below the surface, along with Poseidon's throne room.
Poseidon is found on Mythology Island, which is a Poptropica island.
From Poseidon's statue in the museum.
the pink starfish
In Poseidon's realm, you click on her.
It is in the museum, on the face of Poseidon's statue.
The only doors on Mythology Island are at the temples of Hades and Poseidon, and on the Minotaur's lair.
If you are talking about Mythology Island, there is no such thing there. Mythology Island only has three 'kingdoms': Hades, Poseidon, and Zeus.
Offer the starfish from the Poseidon statue in the Museum.
The offering for Poseidon is a starfish. There is one on the face of his statue in the Museum of Olympus.
His throne room is in the Temple to Poseidon, at the bottom of the lake. But you can only reach it when you have Hercules to move the boulder blocking the entrance. If you accidentally enter the Throne Room by slipping past the rock, you may not be able to get out again unless you have the Transporter Mirror.
zombie poptropica
all you need is Hercules's help