Pigman

With the head of a pig, a butcher's apron, and a meat cleaver to boot, the Pigman is the most dangerous creature in the dark crypts.

Mechanics (Spoilers)
Similar to the Witch, when the Pigman is in your general vicinity, you'll hear music that will intensify as he gets closer. You'll also begin to hear the sound of footsteps and metal jangling when he's dangerously close, as well as some 'oinks', though don't let that lower your guard. If he spots you, he'll squeal loudly and begin to hunt you down. Take as many corners as you can to line-of-sight him, and if he charges at you (you'll hear another loud squeal), try taking a corner quickly. If he hits a wall with the charge, he will be stunned briefly to give you time to get further away.