black magic! what it mean?

Of course man its really really harmful and it is carried with the help of evils,these all black-magicians are cursed people they are dirty peole as the qualifications for acheiving the art of black-magic are very very frustrating ,like one has to eat animal solid waste,or to sit covering the whole body with the blood and solid waste(stool) for 40 days etc.In my Relgion Islam it is prohibbeted to an extent that the one who does this will no longer be a Muslim.