Beekle by Dan Santat

Beekle is an imaginary friend.  He lives on a imaginary island with imaginary friends.  Beekle waits and waits to be picked by a kid but his day never comes.  He will do the unimaginable and sails to our land and finds his friend.  They do the unimaginable together and they have fun.  I think you should defiantly read this book.