Red herring

The Red herring is a quest item used during The Fremennik Trials quest. Once it is cooked, it will become a regular herring, but a new item, sticky red goop, will be created. Once the puzzle involving the red herring has been completed, the herring can be consumed.

'Red herring' is an idiom which refers to something that is seemingly important but is in fact misleading or unimportant. This is ironic, as the red herring is a vital item for solving Peer the Seer's puzzle.