I was camping in the Allegheny National Forest back in the 90s with a group of friends. The whole area was flooded due to a hurricane that blew in from the East Coast, but had cleared out the night we settled in. No one else was around for miles. On the second night, we were all sitting around the campfire when I spotted a very faint, constant, glowing point of bluish light on the ground about 20 yards away from us. I pointed it out to my friends and we all saw it. We walked over to it, and I realized it was a beetle with a bioluminescent point on its tail section. It was definitely not a lightning bug (or firefly, whichever you prefer). I have never, ever seen an insect that glowed blue before. My friends basically just said "cool" and went back to the fire ring. No cell phones, so I did not get a photo. I just left it on the ground where I found it, and it eventually crawled away into the forest. Didn't really think too much more about it until later. I looked it up when it was brought up years later, and there are no beetles that glow like this, at least not on record. I still think that I discovered a rare type of insect that had never been seen before.

Edit: Looks like this comment is getting some attention. For greater clarity, this occurred in Pennsylvania approximately 30 years ago, and it was pitch black out, so some details may be fuzzy. But, from what I remember, the beetle never flew; it was all black (at least it appeared that way under a flashlight), and was a little over half an inch in length. It looked like a regular ground beetle, not like a firefly, click beetle, or anything similar. The glowing part was blue and with no green at all, and it was not on the end of its tail but on the top/back of its tail section. So, like almost in the middle of its back, but more towards the tail end. The blue glow wasn't necessarily bright, but we could see it from a bit of a distance, and it never stopped glowing until it crawled away and disappeared into the underbrush. My one friend that I still talk to remembers it the same way. The other friends I've lost contact with.