Shelob's Poison
The Land of Shadow #60 (x2/x1)
Treachery
Poison.  

When Revealed: Attach to a hero you control and exhaust that hero. (Counts as a Condition attachment with the text: "Limit 1 per hero. Treat attached hero's text box as blank, except for Traits. Attached hero cannot ready.")

Shadow: If attacking enemy is Shelob, resolve the 'When Revealed' effect on Shelob's Poison.