Looks like a T-Rex.
I think Mike has a point. I do place things in buildings, not the stuff Mike mentioned, coins with the right date on them, and one a written note, names, dates of progress, major events and such. No ox eyes, cats eyes maybe. One building had some granite work going on, the workers were cutting 2" holes for some reason, the plugs were laying around. I had a misplaced 2" bore hole, I caught myself after the first hole and stopped the mortice work. I still used the timber, just left it blank. We showed up and commenced to raise the building and found the granite plugs. It was so easy to stick a quarter in the hole and shove the plug in on top of it.
Dave, what is the date on the building? 1987?