Dandelo, also using the name of Joe Collins, was a psychic vampire that lived in a cottage on Odd Lane in the White Lands of Empathica. He kept a horse named Lippy in the stable behind his cottage. At some point, Dandelo captured the artist Patrick Danville and kept him prisoner as a "food source." He later tore out Danville's tongue to prevent the boy from speaking.
He encountered Roland Deschain and Susannah Holmes on their way to the Dark Tower, treating them to a feast. Afterward, he explained that before entering All-world, he was a stand-up comedian. Roland asked to hear some of his act, during which Dandelo came close to making Roland laugh to death. Susannah avoided the trap because she is in the bathroom at the time, tending to a troublesome sore on her face; there she discovered a note apparently left by Stephen King himself (the note even acknowledges itself as a deus ex machina) that helps her puzzle out Joe's true identity.
Before he could drain all of Roland's life force, Dandelo was killed by Susannah with two shots to the head.