There was a period of about a year where every time I would trip on various substances, my tripmates would inevitably turn to me an tell me that I looked like Satan to them. It wasn't malicious or fearful, oddly enough. They just said I had a demeanor that made me satan-like to them.
I know think that (aside from having a goatee) it was simply because I was internally in a bad place, which I was very private about, and they were simply seeing through my egoic front.
All of us contain within ourselves the multitudinous nature of the universe, the darker aspects included, perhaps you were just glimpsing an aspect that they reflected to you at that time.
Or perhaps your friend is the Prince of Darkness