A combination of the words gastronomy and catastrophe; a gastrotastrophe is meal so ruinous with grease, fat, salt and/or hot sauce that you can actually feel your stomach lining peel away like old wall paper, simply at the sight of it. A gastrotastrophe is the culinary equivalent of the kind of thing Harry Truman would order to end a war.
Gary ate 7 pork rind tacos last night and then washed it all down with 9 'Mocha-Madness Mountain Dews" and a funnel cake. It was a gastrotastrophe. He's still on the toilet with a bowl of ice.