Harvey Sandman or just The Sandman that appeared in "Beddy Bye", he is the magical being in charge of all things relating to sleep.
On Earth, his name is Harvey Sandman. He owns a mattress company and is known to the human world as The Mattress King. He hypnotizes people, such as Timmy's dad, into buying his mattresses despite the number they already have bought from him.
Every sleeping wish has to go through him, not a fairy godparent, since he is the master of sleep. And if people aren't getting enough sleep, he shrinks.