A pancreatic pseudocyst forms when fibrous tissue surrounds liquefactive necrotic tissue of the pancreas, and this fibrous tissue develops a cavity that fills up with pancreatic juice.
Pancreatic juice is kinda like the Neapolitan Ice Cream of bodily secretions — it's like everybody's favorite ingredients all put together, and when you mix them, the result is especially powerful.
With gallstones what happens is that they sometimes get lodged at the sphincter of Oddi which blocks the release of pancreatic juices, which is pretty similar to the alcohol-induced protein plug.
Here, it dissolves the fats floating in the slurry of chyme so they can be easily digested by the pancreatic and intestinal juices that have leached onto the scene.