The Spectral event was implimented by Zorg on Friday October 23rd 2009. It lasts from midnight on Friday to midnight on Sunday, server time. You will know when the event has started, as the beginning and end of the event is announced by System on Side Chat.
There are 3 Spectral Items, and each week a single Spectral Item will spawn and be given to a random un-injured avatar who has space in their inventory to carry it. There are two ways to gain an item when the event is going on:
1) Randomly picked to get it from the abyss, or
2) Kill the current carrier and earn a banner when doing so.

Item: Forgotten Amulet Level: 80 Type: Misc. Banner: Screenshot of the Amulet's stats

Item: Shard of Destruction Level: 80 Type: Melee Weapon. Banner: Screenshot of the Shard's stats

Item: Phantom Armour Level: 80 Type: Armour Banner: Screenshot of the Armours stats