How do I Delete this Rock?

I downloaded a build from the gallery but I was unable to delete these rocks that came with it in the basement. I've tried everything from putting a wall through it without bb. moveobjects, creating a room around it and deleting the room, to going in live mode and ctrl-shift clicking it to delete. When I try to use the hammer tool it keeps telling me that "This object can't be deleted". I've also tried going in live mode to try putting in inventory or "digging" it up but it isn't letting me. It's getting super annoying.

(I've attached screenshot)

I really appreciate any help!