The egg
Once upstairs, the expert pointed at a spot on the floor. Susan estimated they were right above where the egg was hanging. Susan looked down and saw some construction foam, that had been sprayed there during a recent redecoration. Part of the foam seemed to have collapsed.
The exterminator told her that there was a hole in the ceiling, or floor, through which the foam had seeped down. This was probably due to it melting and softening in the summer heat. One floor down, it had formed an egg-like shape that had stuck to the ceiling.
Mystery solved!
Source: Fiction | Images: Pexels, iStock, YouTube video stills