Jake yet again said:

Yup, that's right. He is referred to as the Twin Obscenity, together with his "brother" Lloigor (no obvious link to the lloigor race)

Maybe you are actually fighting two GOOs in the Final Battle, and the token is used to show that only one is still left. They could even simultaneously battle both, with the token keeping track of a makeshift doom track of the second one.

Or maybe there is a condition that leads to the appearance of the twin, or something

Solan said:

CAS's Treader of the Dust, surely as a Herald rather than an AO. Very cool, considering it was the top of my list of preferences for new heralds.

/blind assumption