I'm going to relay this story exactly as it happened. You can draw your own conclusions.
When I was in my third year of college, I befriended a guy named Mike who was an archeology major. Over Christmas break he and I came down to the Valley from Flagstaff to work on a construction project with my father.
One day it was raining pretty hard and we couldn't work. Mike suggested that we go to one of the Indian reservations near Phoenix to look for pottery shards and other artifacts. (Don't get on me about his, I was a kid and didn't know any better).
I had never done that and I was interested to go. We drove east on I-10 past the Gila River bridge, turned west off the interstate onto a road that led past the Gila Indian Cultural Center and a ways past there... Perhaps a mile or so... Mike said to pull over and start looking. I told him I didn't know what I was looking for. He said "This," reaching down in front of my feet and picking up a small broken piece of pottery. Obviously a good sign.
Anyway, he showed me how to look for artifacts. I remember in particular how he showed me to dig through the tailings from animal burrows to find things that they have dug up. Doing so we found many, many pieces of pottery as well as broken shell braclets and a few beads and other items.
We gahtered these up. There were so many that our pockets were over flowing. We decided to take what we had found back to my truck and then come back to look some more. As I filled my pockets and turned to go to my truck, out of the corner of my eye I saw a large pot and a small flat basket sitting on a grass matt in a small clearing about 10 to 15 yards from where we were digging. Excited, Mike and I quickly hurried the hundred or so yards back to my truck dropped the artifacts next to the tire and hurried back to the site where we had seen the pot.
When we got there it was gone. Mike and I walked right to the spot and there was nothing there. The clearing was there but nothing else. We walked back and forth to check. I said "You saw that, right?" He said he had, and I asked "Where did it go?" He stood there for a minute looking around and then he turned to me and said..."They're messing with us." I asked "Who?"
He said, "The Indians." I said, "Mike, there's no one here. Where did it go?" He said, "No, not someone. The Indian spirits." I told him I thought that was nuts. He told me that it didn't matter what I thought. He said I saw the pot. He saw the pot and the pot was now gone. He said the spirits wanted us to see it and then take it away to spook us. He said it happened all the time when they went out on digs in the desert. He said things would move, things would disappear, you'd hear voices. He said archeologists don't talk about it but that it happens surprisingly often.
With that, I got creeped out. I couldn't make sense of it. We walked around a few more minutes in the rain and then drove home. We didn't really talk about it again. There was no way to explain it.