Opinions on Nozick's Utility Monster

[Slander and/or Libel]

Having just read Mill's Utilitarianism, I suspect he'd object that the concept of a single entity having the ability to generate such disparate utility would have been laughable under his outline of utilitarianism, where each person is to be weighted equally. He doesn't delve all that deeply into it, but I believe there's an implication of a cap on meaningful utility, or that certain utilities can be weighted as far more fundamental than others.