So did you talk to the friend and get the story of what she was told happened that night?

According to the friend, she was told by your friend V that she saw horns growing out of you? You in the meantime were able to experience and view yourself having these horns?

That's cool, but I've always thought horns are a little silly because they have to do with cows and gazelle and generally peaceful creatures who often get eaten alot and are just herbivores mainly.

The horns are usually used for mating contests I think, like battles.

But really traditional demons, jinns, and whatever are not physical beings but are spirit beings, or the modern idea would be that they are made of a material that is different from us, such as plasma. (The Qur'an describes jinns as being made of "smokeless fire" which can be description of plasma).

Some people believe humans can be possessed by them, but then that contradicts other people's belief in total free will. If we can be controlled, then who is to say that we aren't being controlled right now, whats the difference?

Through art, and dealing with various "pagan" religions, demons came to be associated with horns. It is possible it is also connected with an old entity from Jewish lore known as Azazel who was supposedly a half goat half man type being that was worshipped in the middle east (if this is true that there was such a god or spirit worshipped by people, then it may have been considered a protector of herds). That is a possible link to where the goat connection came from. More recently the goat connection was made through the trials of the Templars who were supposedly worshipping a goat headed being called Baphomet (which some might have thought was a mistranslation of Mohammed).

There are lots of routes to go for research. In the end it will come to what you're willing to believe and what you're willing to settle on.

I've come to the belief that nothing can be known for certain, because even if we know something, we can't know we know it for sure.

Belief in extra dimensionals relies on many other beliefs for it to be believable to the person. In other words you will need to accept alot of things to accept that, when none of it might be real or true at all.

Then one might wonder, what beliefs are most beneficial to choose? Those that reduce personal risk probably.

There could be many psychological explanations of what happened too.

So then you're left with some choices again.

The external explanations
and the
The internal explanations

The external explanations could be the following:
An entity controlling you or imposing itself on you
Radiation or frequencies disrupting normal behavior
Pheramones from the girl, chemicals from the candle, allergins etc

Internal explanations could be:
That you had an episode based on psychological reasons

You could say, if it was an episode you experienced, how did the girl see it too

If it was a hallucination caused by the candle, the girl took in the same chemicals, but how then did she hallucinate the same thing.

So that would lead to the belief in either a shared hallucination, or the event physically happening, so anyone there would've witnessed it.

You can't know which it is for certain. She was the only other witness, and if it doesn't happen again then she will be the only witness. Plus she forgot which is troublesome.

Dual hallucination requires some beliefs, such as the belief in hallucinations and then the belief that hallucinations can somehow be shared.