The lyrics to the "Wishing" song, which The Psammead performs during the closing credits are: When you want your heart's desire/And there's nothing but the fire/Of a madly yearning wild imagination/When all you have to do is choose/And if you don't you're bound to lose/Something special in your life will pass you by/Castles in the air/Or a chest purest gold/Start a quest/Before you're old/Try wishing/A little harder every day/Wishing/To chase the clouds away!/In the twinkling of an eye/You'll grow tall/or even fly/You won't know until you try/So do/And in the magic that you find/Dream your dream away.
In the book, the Psammead has eyes at the ends of stalks. The BBC creature designers considered this too grotesque, and made his face more humanoid.