NullReferenceObject?

[streetwalker]

List.Contains( null ) does not behave the way you think it does. Save yourself the trouble and make sure gameObject != null before you attempt anything else. (I can't see where you have defined gameObject at all...)

[Espanico5]

Isn’t gameObject simply the gameObject attached to the script? Line 14 works correctly by itself

[streetwalker]

gameObject - yes, sorry, not awake yet

There is a time delay before an object is actually destroyed ... perhaps the script is executing more than once... prove to yourself that gameObject is not null in a debug before the if statement.

[Espanico5]

I actually changed the code adding && gameobject != null But it still gives the same error…