testing if an object is null

[Mutant_Fruit]

Then your overloaded operator should do a nullcheck before it does the usual equality check.

Alternatively if you cast to 'object' first, you'll use the regular (non-overloaded) comparison:

if ((object)myObject == null) {
    Console.WriteLine ("I'm using the regular '==' and i'm null");
}

EDIT: Generally speaking you should only override == for immutable types. So if your type is mutable, then don't override '=='. If you want value comparison, you should be overriding the 'Equals' method.