What's this mean?

[OliveTheGreat]

[Yee]

That means that there’s a reference missing, for instance:

Transform _myTransform = null;

private void Start()
{
    Debug.Log(_myTransform);
}

That code returns the same error since the variable _myTransform has no value or has null value, yet I’m trying to access it.

That error also can occur because you forgot to add the value in Unity’s inspector;

[Serialized] Transform _myTransform;

private void Start()
{
    Debug.Log(_myTransform.name);
}

In the code above, if you add nothing in the inspector, the console will mark that same error.

If you get that error and nothing is wrong, there’s a chance you have duplicated scripts somewhere in your project’s hierarchy with no values.

Hope this helps!

[bixarrio]

Also, it tells you that your specific error is in the Dropper.cs on line 14

[Yee]

Unless…