Just casually extruding some faces and then I miss-clicked on the Bridge tool in the Polygons Tool Bar and a hole was created and the model just disappeared and you can only see it in the wire frame view port.

https://gyazo.com/4d389eb6b1886682b45d8859a1d5f472

https://gyazo.com/e8b7cdb6f7af04c55aa6d2d73d11eae3