Many Wyrm-spirits are masters of deception and deceit in the physical world, taking false forms as they lead their victims into acts of sin and desperation. Of course, humans have enough of a survival instinct to fear or mistrust the people and places acting as hosts to these spirits. (“He was such a quiet man, officer — he kept mostly to himself.”) The sight of the Wyrm in its true and hideous guise is enough to overwhelm a human mind with the madness of the Delirium.

In the Umbra, these deceptions are less important. Wyrm spirits appear as corrupt, unhealthy, unwholesome, vile, or insane. As amalgams of all that is antithetical to the life-giving energy of the Wyld, they may appear as toxic, irradiated, primeval, diseased, engorged, tentacular, sinful, grossly monstrous, or pathetic. Like the offspring of desperately breeding horrors, articulated by an elaborate parade of Lovecraftian adjectives, they can transform any object into a personification of madness and savage horror.