The battle over proposed cuts to private Medicare plans is heating up, as the liberal group Americans United for Change released a Halloween-themed ad protesting what it called Republican "fear mongering" over proposed cuts in Medicare Advantage amounting to $100 billion over a decade. The ad takes on Humana Inc. Chief Executive Michael B. McCallister and GOP leaders who oppose the spending cuts and the Medicare agency's effort to stop Humana from enlisting seniors in its fight.