How would I got about loading, and saving a Unit?

How would I got about loading, and saving a Unit?

I want to make an evolution system but I don’t know how I would do it as I don’t know anyway to get the exact unit that the player clicks on.

An example is in games like Anime Last Stand/Anime Adventures

games like PSX, P99 and most likely those anime games you listed all use GUID and when the pet is created, that GUID has a list of variables under it that say what the pet is. To make a GUID, use HttpService with the namecall function GenerateGUID.