Private Corpsepile

 is an undead U.S. soldier (or rather, a pile thereof) encountered in the Government Bunker.

Attacks
The Private will first appear as a pile of corpses and attempt to hit your hero with his club. After dealing enough damage to him, the real fun begins as he falls apart into three separate zombie soldiers. The Private will continue chasing your hero with his club, while the other two corpses (a marksman and a missile launcher operator, apparently) will attempt to shoot your hero down. The rockets are particularly damaging, as they knock the hero about leaving them vulnerable.

Strategy
The strategy is simple: First damage the Private enough to force him to fall apart. Next, concentrate on the marksman and the rocket launcher, as while the Private is a tempting target, his attacks are easy to dodge. The rockets and bullets, not so much. Focus on the rockets first, then on the sniper, as you can easily get out of his sights by dashing.

Note that for any challenge that involves Private Corpsepile, he only counts as dead once every element of him is dead. All three corpses from the pile need to go.