There's something about prototypal inheritance...

Let's look at some JavaScript, and today I'll ask Crockford to pass the sugar:

Object.create = function (o) {
    function F() {}
    F.prototype = o;
    return new F();
};

Now let's create an object a, and a two objects b and c based on a.

var a = { name: "a" };
var b = Object.create(a);
var c = Object.create(a);
c.name = "c";

At this point both a and b have name "a", and c has a customized name "c". Now lets change a:

a.name = "foo";

Objects a and b now have name "foo", and c still gets to keep name "c" (a good language design decision methinks). Since a is just a mutable object we wield this sort of godly power to change or inject DNA. Every time I come back to it, it tickles me.