title: Change prototype of a prototype to affect instance JS
body: <p>I have an instance of a class, but I don't have access to that instance, only to the class itself. Can I modify the prototype of the class so that the instance receives an update to its methods also? </p>
  
  <pre><code>class B { c() { console.log('B') } }
  class C { c() { console.log('C') } }
  const b = new B // newbie :P
  // now no access to b
  // I want:
  B.prototype.__proto__ = C.prototype
  // now yes access to b
  b.c() // prints C
  </code></pre>