Prototype & Prototypal Inheritance

function Mammal() {}
function Bird() {}

const bat = new Mammal();

Object.setPrototypeOf(bat, Bird.prototype);

It's not possible to change the prototype after creation
It will cause syntax errors
It can lead to inconsistent behavior
It can severely impact performance
Changing an object's prototype after creation with Object.setPrototypeOf() can severely impact performance because: 1) JavaScript engines optimize property access based on the initial prototype structure, 2) Changing the prototype invalidates these optimizations, 3) It requires the engine to reoptimize object property lookups, 4) Modern JavaScript engines specially optimize object creation patterns but not prototype changes, 5) All browsers explicitly warn against this in their documentation, 6) Better alternatives include creating objects with the desired prototype initially with Object.create(). This operation can be up to 100x slower than normal property access.