random falling of objects

Hello! I have a question. I have let the chest and when I opened it and there should appear things I want to do that would be when you open it you have always been different things as I do that? randomly or I do not know tell me what kind of event or function should be.

When you open a chest you want the item to be random?

I need to sprite randomly spawning other sprayty.predmety, whatever.