The Voice of Shandoo is an entity voiced by Nick Smith who appeared in True friendship.
It does not have a physical form per se; it exists as a cloud of sound and light, in the shape of a large penis. Appearing in this form was not by the entity's own choice, but rather due to predestined factors. (True friendship deleted scenes)
"We all take different forms. I happen to be in the gas cloud shape of a large penis, yes." — the Voice of Shandoo
"Why would you settle on that?" — Dive Roll Adventurer
"It's not my choice. Some things are predestined." — the Voice of Shandoo