The Wyrm itself is, of course, the natural and positive source and cause of destruction, and so the source of destruction in the Garou is tinged by it. (Garou with Rage of 7 or above do show faintly in Sense Wyrm, for example.)
But given as the Wyrm itself is corrupted, so too is the Garou's Rage, and those Garou who give in to it completely end up in a frenzy which is unstoppable, mindless, and truly terrifying.
Mechanically, if the player gets 6 successes, they enter a Berserk frenzy, with no chance of Willpower staving it off. The frenzy follows normal tendencies with regards to attacks and duration, but it includes some even more horrific aspects.
Specifically, players must roll Wits (difficulty 7). If the roll botches, the characters give in to a particular aspect of the Wyrm.
Homid Garou: They give in to the Eater of Souls, who has long held humans (and homid Garou) as its special children. The Wyrm can drive such Garou to acts of cannibalism upon humans, wolves or even other Garou. If they botch their Wits roll, they must feed on their nearest and dearest.
Metis Garou: Barred as they are from breeding, metis are special targets of the Defiler Wyrm. Metis Garou in the Thrall sometimes practice unspeakable acts of perversion on fallen opponents. If they botch their Wits roll, the Garou stops fighting for a turn and slakes her unholy lust on her helpless opponent.
Lupus Garou: The savage, feral lupus feel the pull of Beast-of-War. A lupus Garou in the thrall will savage a fallen opponent, friend or foe, and not pull away until the body lies in pieces around her. The Garou loses all sense of mercy. When a lupus Garou kills or incapacitates a foe while in the Thrall, her player must roll Wits (difficulty 7). If the roll botches, the lupus must continue to attack until her opponent is torn limb from limb.
Succumbing to the Thrall of the Wyrm is terrifying to the Garou. A normal frenzy is considered a defense mechanism against pain or overwhelming anger, a pure if brutal method of survival. A Wyrm-frenzy is nothing of the kind. It brings to light the inner struggle with the Wyrm, which is something few Garou are prepared to face. Unable to live with their deed, some werewolves even end their lives after such a frenzy.