I think you missed where I mentioned, use code tags. Using code tags properly
Please edit your post so people can read it a lot easier.
Edit: Also, this.
As I said, you’re simply destroying something that still has a reference. It’s pretty straight forward. Once again, static is a keyword that I mentioned for you to look for. A static list that is made up of instances that get destroyed will start throwing errors when it can’t find those items anymore.
public static List<SkeletonBasic> Instances = new List<SkeletonBasic>();