Giant Undead Rat

Giant Rat is a mini boss found in the sewers.

Strategy
There is a hidden passageway behind a destroyable box where you first meet the butcher as you enter the sewers. Drop down the shortcut (you may take fall damage), and you'll end up one level above the Giant Rat. From there, you can use any projectile or throwing weapons, and you will be able to dispatch the Giant Rat without even having to confront it.