Sorry, I'm not typing these up and burying them in an old post. ;) But here are some creepy SAR stories for you. Possible TW, some of these involve suicide and death but not in graphic detail.
One of the weirdest things I experienced was before I was involved in K9 SAR and was just on a ground team. We were in the Pecos looking for a possible suicide victim who was last seen wearing a light blue jacket and black pants. When you're doing a ground search, you basically spread out to cover as much ground as possible and then just grid the area. So I was on this three-person team. I was in the middle.
So about 5 hours into the search the person to my left starts seeing flashes of light blue ahead of us (like catching glimpses of someone in those clothes through the trees), but we can't find anything and while there's a lot of deadfall we'd be able to see someone standing/walking pretty easily because the trees are fairly spaced out and clear in between. We walk for about half an hour and he suddenly sees light blue behind us.
We went back to investigate and found the subject beneath a couple of fallen trees that had sort of created this natural shelter low to the ground against the side of a hill. There was pretty much no way my teammate could have seen his shirt from where he was, and he saw it at the height a person standing would be, not down on the ground.
One I personally experienced was in the Gila, which is my usual stomping grounds. We were out there with my GSD looking for a missing hunter (we being me and one of my teammates who was acting as field support). Our search assignment was to clear the trail he was on when he was last seen. We were about two hours out from the PLS and had accidentally gotten onto a side trail. Basically, we were following the original route of the trail according to the topo maps that IC gave us, but those maps turned out to be really out of date (they were NAD27, which we discovered during our debriefing as the copied maps with our route marked didn't have the datum on them). But it was apparently part of the original trail, but no more.
The trail on the NAD27 map and the more recently surveyed map on my GPS were close enough that we weren't sure which one we were supposed to follow at the fork, and we chose the NAD27 trail as it initially appeared to be more heavily trafficked. It fairly quickly became overgrown but we still weren't sure because the GPS showed that we were off the mapped trail, but we'd figured by then that it was different datum (my GPS was set to WGS84 as that was the most commonly used one for the time/location and IC was kind of a mess due to the early stage of the search and the person who briefed us wasn't sure what the map datum was) and we weren't really very far off at all so we thought it was possible that we were on the right trail and it was just a slight deviation. It also occurred to us that our subject could have made the same mistake and just gotten lost that way, so on both accounts we thought it was worth following.
So we followed this trail for maybe an hour. It was increasingly overgrown but still clear and visible. My dog is an air scent dog so he was roaming far and wide because he has a pretty wide range. But all of a sudden he came back and was glued to my side, refusing to go out again.
About the same time we rounded a bend and saw this shack. It was made of cinder blocks, which was weird already because those are heavy and difficult to tote in, an this was difficult terrain with no roads so someone would have had to pack them in. There was a metal door that was ajar. There was one tiny window set high in one wall. The roof was caved in and the window was broken.
My dog's hackles were up all along his back from shoulder to tail and he kept blocking me when I tried to approach the shack, which is totally out of character for him. He was clearly afraid. He was only live certified at the time so we discussed maybe it being the scent of a body that scared him, but that didn't make sense because he was training to be a cadaver dog and had never shown fear. But we convinced ourselves that it was either that or a bear or something in the area (nevermind we had bears in our yard pretty often and he never freaked out but...) and cleared the area. We kind of had to because lost or injured persons usually seek shelters like that.
My teammate went around the shack and I stepped into it. I couldn't get very far because there was a ton of rusty dangerous junk in it, most of which I couldn't identify. But there was definitely no person in there, and I have never felt such a strong RUN NOW NO MATTER WHAT! impulse as I did when I stepped through that doorway. There were brown stains all along the walls that I think were probably rust from all the metal junk but in the moment they sure looked like bloodstains.
My teammate came around the corner right as I stepped out and we both were like "NOPE!" and went back down the trail as quick as we safely could. We took the other fork when we got back, and later located our subject about 4 miles away on a ridge top he had gotten to in an attempt to attract a helicopter.
I've got some more but there's a couple to tide you over. ;) Hope Eyeball in my AcidMartini doesn't mind the use of the tag...