So, another question of the queen of fiends.

Necrofear can be equiped to a face down monster?, i have seen many people do this before.

Absolutly not. Face-down cards cannot be equipped.

Likewise, if Necrofear equipped itself to a monster and that monster was later turned face-down by an effect, like Book of Moon, then then the equip would be considered illegal and the equip (Necrofear) would be destroyed.