The act of defecating in the tank of a toilet that has a bladder in it. With gravity, the feces will then move it's way in between the inside portion of the tank and bladder.
Since no water is present to flush the feces down, it will sit until someone cleans it. This act then requires the person who is cleaning it to dismantle the entire toilet, making the toilet technically "wrecked" until it is cleaned.
Most of the time hotels use these bladders, but also can be found in residential areas. Also see; UppderDecker, Upper Decker,
After I lifted the lid on the tank, I realized I was going to be leaving a upperwrecker.