Pighead

The Pighead is the mysterious enforcer that serves Jigsaw in the SAW franchise. It is never revealed as to who the identity of the Pighead is, although hints have been given.

SAW

The Pighead in SAW was increasingly antagonistic to David Tapp, the focus of Jigsaw's test in the insane asylum. At first, relying on jump scares and surprise attacks, he kept Tapp in line and fitted him with the monstrous shotgun collar that he wears throughout most of the game. Toward the end, however, he takes it upon himself to kill Tapp in an attempt to undermine Jigsaw's authority, and Tapp kills him in self-defense.

SAW II: Flesh & Blood

The Pighead in SAW II is decidedly more reliable to Jigsaw's needs and is surprisingly non-threatening to Michael Tapp, the focus of Jigsaw's test. Despite that, he does intervene once, supposedly with Jigsaw's blessing, by killing the corrupt police chief Henry Jacobs. The Pighead is hinted to be a known associate of David Tapp by Sarah Blalock before she is killed by Joseph Poltzer. This has lead many SAW fans to speculate the identity of this Pighead is actually Detective Mark Hoffman, before he became the chief antagonist of the film series when Jigsaw is ultimately killed in the film SAW 3. It's also possible that he is Jennings Foster, the only other person at David Tapp's apartment who wasn't kidnapped. He was also once a Jigsaw victim himself (in the first SAW game) and Jigsaw survivors seem to have a tendency to become Jigsaw followers in this series.