The reason for this error is it's attempting to remove something from the list @ index spawnObject, which is 38660.
You're going to need to iterate the list, and find the entry with the id of 38660. I would suggest using https://docs.oracle.com/javase/8/doc...ion.Predicate- Collection.removeIf to accomplish this, although I believe that will only work if you're running Java 8.