It's off of the newest album, Then and Again. In all sincerity, it's a somewhat playful, but ultimately serious lullaby that Voltaire wrote for his son. He confronts the typical monsters under the bed that a young child fears and tells him that he won't claim that they don't exist, but instead, will teach his son to be strong and defeat them. At the end, there's a profound universal truth to it all and these are my favourite lines:
"This world of ours is not as it seems
The monsters are real, but they're not in your dreams
Learn what you can from the beasts you defeat
You'll need it for some of the people you meet"

It actually makes me get teary-eyed sometimes...