C# Extension Method for Object

Question

Is it a good idea to use an extension method on the Object class?

I was wondering if by registering this method if you were incurring a performance penalty as it would b

Answer 1

In addition to another answers:

there would be no performance penalty because extension methods is compiler feature. Consider following code:

public static class MyExtensions
{
    public static void MyMethod(this object) { ... }
} 

object obj = new object();
obj.MyMethod();

The call to MyMethod will be actually compiled to:

MyExtensions.MyMethod(obj);