Abyssal Shadow

The Abyssal Shadow is an item dropped by Aquatic Hallucinations that summons Abyssion, The Forgotten One in the Aquatic Depths. Prior to defeating Abyssion, this item cannot legitimately appear in the player's inventory; it is used upon pickup. Upon pickup, it inflicts the False Presence debuff; after obtaining three stacks of the debuff, the boss will spawn.

After the player has defeated Abyssion at least once, the Abyssal Shadow will behave like a traditional summoning item for the boss.