Some of the vinegar will also sneak through the egg's membrane (permeate the membrane) and cause the egg to get a little bigger. That's why the egg is even more delicate if you handle it. If you shake the egg, you can see the yolk sloshing around in the egg white. If the membrane breaks, the egg's insides will spill out into the vinegar. Yes, you've made a pickled egg. The longer you leave the egg in the vinegar, the more it changes. Its shell will become a material that feels like a rubber ball. After a period of 4 weeks the egg will become bouncy.