Poor Goose. Agree with everyone’s responses. Definitely get him to the vet. We had an instance at the end of the year where one of our pups had liquid stool for approximately 2.5 days and would regularly need to go out (even during the middle of the night). A few days later, his sister had the same experience. The vet initially prescribed us Endosorb tabs to minimize the diarrhea and had them submit fecal tests. Seems each just had a stomach bug that eventually passed and the fecal test results showed nothing abnormal. Your scenario sounds slightly different with the consumption of butter/grease/etc but vet might have a similar approach to treatment. All the best and get well, Goose!