I don't know what defines a campfire story, but here's a random personal experience with one scary moment.

This story has three layers. 

The first part is about how I was best friends with this certain kid when I was like 12. He was my dad's boss's son. He was about a year or two older than me and he used to listen to ICP, scavenge his older sister's bedroom for "toys", masturbate while I was in the room, wipe his mess on the side of his bed, mod nipples onto his Sims characters, trick me into saying dirty words I didn't understand, and somehow convince me he was a normal person. (That's all I remember off the top of my head)

The second part is how we went trick-or-treating on Halloween one time as the members of ICP. Yeah, you heard right. I didn't know what the fuck I was doing, so lay off. Anyway, we came across a house with a bowl of candy out front and a sign that read "take one." After going back and taking multiple handfuls, the man opened his front door and confronted us. He told us to come inside, and we actually did. *dramatic pause* Luckily for me, instead of being molested that night I was only shown a framed police badge and given a firm talking to.

The third part of the story is how I haven't seen this dude in years and the last I heard he was strung out on meth.

Edit:

Also I've had sleep paralysis a few times, which can be incredibly convincing as something paranormal. Absolutely terrifying.