Here's the text on the Sacked! card:
Treachery
When revealed: Attach to a hero with no "Sacked!" cards attached controlled by the first player. (Cannot be cancelled.) Counts as a Condition attachment with the text: "Attached hero cannot attack, defend, commit to a quest, trigger its effect, or collect resources."
Shadow: If attacking ennemy is a troll, resolve this card's "when revealed" effect.
2 questions (basically, how would you rule it):
- If Sacked! is revealed as a shadow card, can you cancel it with Hasty Stroke? The "treachery" portion (regular when revealed effect) can't be cancelled (no Eleanor nor A Test of Will), but the "shadow" needs to resolve first before you resolve the top portion of the card ("when revealed"). I'd rule that you can use Hasty Stroke to cancel it.
- How would you resolve it if all heroes controlled by the first player already have Sacked! cards attached to them? Simply discard the just revealed card?