The 'trunk' either representing the blood shed from their sacrifice and/or the people, pigs and Manpigs slaughtered by The Machine. The heart may be a symbol for the hearts torn out of Edwin and Enoch, and/or the heart of The Machine itself.

The markings on its forehead likely represent the Orb on its mantle, with a heart surrounded by a red tree trunk-like shape below.

It's possible that the ghosts of Mandus' deceased children are moving the mask, guiding Mandus towards redemption.

Or it might just be a figment of Mandus' broken psyche haunting him.

The Pig Mask might also be a representation of The Engineer, looming after Mandus and watching him proceed through his journey.

But like with Daniel, it's always watching, always knowing where the businessman is. It seems content to just watch Mandus to see what he'll do without interfering him. Like with Daniel, it's constantly pursuing Oswald, though unlike with Daniel, is not directly attacking him, or actively hunting him.

The Pig Mask might be an alternate, more physical form, of the guardian of the orbs, the Shadow from Amnesia: The Dark Descent.

Many Pig Masks rain down upon a note explaining what fate befell his children, Edwin and Enoch Mandus.

Though it never directly harms Oswald, it does manage at least one jump-scare in the game when it flashes briefly before Mandus' sight while climbing a ladder in the Bilge Pumps. It has a weird sinister grin, though depending on what angle one looks at it, or what position its staring at Mandus, it's either mockingly jeering at him, or is giving off a dejected angry glare. It would appear to be of Mesoamerica origin, but the lines, markings, and other features on it are very strange, especially the orb on its forehead with miniature stars adorning it. It often switches places just to confuse him. Oswald never once sees it move directly after him, however he comes to realise it is always unnervingly following either just behind him, or one step ahead of him. The Pig Mask is a mysterious item that silently stalks after Oswald Mandus throughout Amnesia: A Machine for Pigs.

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