If you're looking for the fairy tale verison, then please look somewere else; this isn't the fairy tale version! There may be slight varitations to this:
During the time of the story in which it was set, witches loved wearing red hoods.
A witch had entered the forest when a man confronted the witch and told her that he wanted to be a werewolf. She fufilled his request. Instantly, he turned to a wolf. She then walked on to visit her Grandmother.
The man had lost all recognition of people except his own voice, so he raced to the witch's grandmother's house then hid the grandmother and lay in the bed.
The witch entered the house and noticed all the features of her grandmother. The wolf chased her but was killed.