In the Stooges short "Three Hams on Rye," the Three Stooges become part of a play. At the end of the play, they are to each consume cake. Instead of a cake, however, the Stooges accidentally cooked a pot holder. So they're struggling to cut their individual slices of cake, and having even more trouble swallowing them.
There appear to be feathers from the pot holders in the Stooges' mouths, which is certainly possible, but at the end of the scene, the Stooges and other actors in the play cough up the feathers. How was this filmed? It seems unlikely that the actors could have kept the feathers in their mouths without gagging, and it would be an obvious choking risk.
Yet, they look like real feathers, and it looks like they're really being coughed out of their mouths.