Plumbobus literalite found

I've been looking and even on guides, the plumbobus is something you send in to get, but this didn't happen in my game.

I don't mess with elements. My Sims were at work. There are no lot traits. They live at the Rustic Residence in Windingburg, or whatever it's called. It may have been storming. While they were at work, I put paintings and plants in the family inventory so they wouldn't be lost, because I was planning on them moving after they got off of work. My female was finishing a painting and I happened to see a clear cube on the ground and then the literalite. There's no lot trait and you aren't supposed to just find them, so why 2 rare things on my lot? Did they put a hidden trait on the rustic residence? Was it a result of thunder storms?