Actually managed that once. Basement was half finished by the previous owners but left a hole for the well window. The result was a gap between the window and the drywall. Cat wanted to look out the window and ended up falling onto the insulation. He cried for a while until we figured out where he was, and when we grabbed a ladder to mount a rescue he hauled his own happy ass out unassisted. Same cat also managed to find a way ABOVE the ceiling of a basement closet.