He can be summoned by clicking the Ever-Burning Lamp and he will yell “PHENOMENAL COSMIC POWERS! Itty bitty living space” which is a reference to Robin Williams’ role as Genie in Disney’s Aladdin. Other references can be found around the island.
Like the large egg with a chair and some machinery inside which is a reference to his role as Mork the alien who comes to Earth in an egg-like spaceship in the TV series Mork & Mindy.
Some toys can be found behind a tree, which I read is a reference to the movie Toys.
A murloc riding an elekk can be found higher up on the island.
Have you visited Robin on his island?