LOL! - I know you were just using a cliche, but it was too tempting to let the dig go by ...
I do not remember the specifics, but basically the Koran states that Mohammad was in a cave and he received a revelation from some 'spirit' that led him to make a mistake. He claimed that this lying spirit was the Devil. He was undoubtedly correct, but he failed to note that all of his other inspiration also came from Satan.
Deuteronomy 18 describes how we should deal with such false prophets:
Deuteronomy 18
20 But the prophet, which shall presume to speak a word in my name, which I have not commanded him to speak, or that shall speak in the name of other gods, even that prophet shall die.
21 And if thou say in thine heart, How shall we know the word which the Lord hath not spoken?
22 When a prophet speaketh in the name of the Lord, if the thing follow not, nor come to pass, that is the thing which the Lord hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.
Oh, I agree that he is a false prophet.
But remember the saying about broken clocks occasionally being right. It is hard to be 100% wrong, even if one tries.
Ok, take care, and thanks for teaching me something.