The is the greatest offence ever created, it is the brain child of the person who added it to the urban dictionary. The phrase (Homo-incestual-pyro-negro philiac) means, someone who has sex with someone the same sex as them, related to them, whilst they are dead and on fire.
An example of Homo-incestual-pyro-negro philiac is:
A Boy walks into a grave yard finds his great great great uncle, digs him up, sets the corpes alight and has sex with it.