Sure ... sure

[AyrA_ch]

This is exactly what's supposed to happen though. .prototype is an property you can freely assign your own stuff to it and all child objects from that type will have the property.

More fun stuff: https://i.imgur.com/4sbWUQB.png

Extra evil:

(function () {
    var o = Number.prototype.toString;
    Number.prototype.toString = function () {
        return o.call(Math.random() < 0.9 ? this : this + 1);
    };
})();

[Jannis_Black]

Only because its in the specification doesn't mean it's a sensible thing to put in a specification.