If my memory is correct, the Bible does say that the enemy can appear as an “angel of light”, and it is said that the angel who appeared to Muhammed was an angel in light.
Galatians 1:8
But even if we or an angel from heaven should preach (to you) a gospel other than the one that we preached to you, let that one be accursed!
Mo’ was probably just starving and having hallucinations. You can only live on goat and camel droppings for so long.