Enemy appearences

I want to know how to make something appear on screen after going in a room but appear at a different time the next time you go into a room. How do I do this?

I’m not sure I understand this question. You want to have an object appear after a delay when you enter a room, but the delay is different each time?

I think that I can do it now that there’s a specific level on the “next room” icon. Sorry for your trouble.