He visited the island with a tour group, but got lost. Not knowing how to read, he couldn't read the signs or map and was left behind. He moved into a cave and furnished it as a home.
He and Sapphire Trollzawa met when he saved her from a coconut attack by the Angry Palm Trees, one of the monsters awakened by the magical battle between Simon and the BFFL.
She confessed her inability to swim, and he his inability to read. They made a deal to teach each other. Sapphire gave him the nickname "Sandy", which he liked, and usually called her "Sapphire-friend".
He saved the island by reading aloud the spell to put all the monsters back to sleep, and afterwards left for home with the help of a dolphin who had been changed into a sea serpent.
Sandstone stands about seven feet tall, and is rather broad, with dark green skin, large ears, claws and pointed teeth. He also has a beard. He wears crude clothes and speaks in simpler sentences, but is not stupid. Despilte his fearsome appearance he is friendly and willing to help.