Skull Rock

Skull Rock is a large stone monolith located offshore of the island in Neverland.

Unlike the rest of Neverland, Skull Rock was created when Rumplestiltskin's father made the decision to stay on the island.

Before the Curse
After Rumplestiltskin's father made the decision to abandon Rumple to become young again and stay in Neverland, Skull Rock was created via magic. Inside the rock he was informed by the Shadow by a large hourglass that once it is empty his youth would one day be taken and he would die. Shocked thinking he would remain young forever, Rumple's father declared he would find a way to remain young forever in Neverland. This would be the beginnings of his search for the Heart of the Truest Believer.

After the Curse
Pan tricked Henry into thinking Skull Rock was the place where Neverland's magic emanated from and that to save Neverland he would need to do it in Skull Rock. Emma, Regina, Rumplestiltskin and Neal would head there after Wendy informed them to confront Pan and Henry, they were unsuccesful and Rumple was trapped inside Pandora's Box while Henry gave Pan his heart. Pan would then leave Skull Rock and fly back to the main island while the others did so as well.

Physical geography
While Skull Rock is primarily rock, there is inside a large hourglass presumably made of magic. As well as many skulls.