I have some prefabs for badguys and bosses. The first time one is instantiated there is a small freeze, and after that it doesn’t lag whenever one is instantiated. It looks like Resources.Load just returns a link to an object. I would like to just do this when level two ends: Resources.Load(“Level 3”); and have all the prefabs for level three be preloaded right when level two ends. Would this work? If not, what is the real way to do this?
I don’t know if it would work, but you could also have a script on your newly loaded level that on Awake() or Start() loads one of each of your prefabs then destroys or inactivates them. It will take your level a little longer to load. You might also be able to use a separate thread or a coroutine, but I have never done either one of those in Unitys so I am not quit sure. Now if I only had your creative brain for all the great ideas you come up with 
I should try instantiating and deleting each prefab. I had thought of it before but for some reason I never tried it.