Witches do not exist. Ghosts do not exist. Mediums do not exist. Magic does not exist. Christians need not believe any of these exist, in fact you cannot believe they exist. They are superstitious and idolatrous beliefs.
>inb4 but they are mentioned in the Bible!
It does not follow that because the Bible mentions them that it's teaching they actually exist or have any actual power, no more than the Bible mentioning other gods implies those gods exist. IF any supposed power does seem to result from their acts then it is nothing more than illusion, which can be explained either naturally or because God allowed it. In fact witches and mediums can do nothing supernatural at all, neither can demons, unless God allows it. Do you really think the witch of Endor actually summoned Samuel? Only God can allow the dead to appear the living assuming the phantom that appeared was even the prophet at all or assuming the story is even completely literal. Anyway there is no magic, no ghosts, no mediums, no magic. None. Zip. Zilch. 99.9% of the time any supposed witchcraft or hauntings have natural, scientific, explanations. The very few that may not are either because God, in his sovereignty and providence, allowed for it, or because of demonic activity, which actually also God allows.