The title of this song sounds like it could be straight out of a horror movie. But it's actually more sappy than scary, highlighting the idea that ghosts are simply a metaphor for relationships that ended in divorce or death.
The song was originally released as an instrumental track but after its success he enlisted the help of Rob Swire (Pendulum and Knife Party) to add vocals. The result was an eerie electro-house jam that became one of the most popular dance songs of its era.
In the music video for the song Deadmau5 appears to be having an 'out of body experience', this shows that he is in the 'liminal' state between the living and the dead. During this time the ghost visits a host of different places including the burger shop and tattoo parlor, these are all Low-Culture stores, they represent the social alienation that the ghost experiences when he is in 'limbo'.
Once he is out of 'limbo' the ghost travels to a range of other locations including a laundry, this represents his re-cleansing after he has had a bad trip. He then gets a Space Invader tattoo, this is a symbol for his redemption. Finally he goes to a disco, this is an area of society that is often seen as a place of celebration, it may be to show that after the 'out of body' experience he has become a part of this world again.