The card reads:
Exhaust this card when an attack targeting a villain is declared to add 1 black die to that villain's defense pool.
---------
1 thread: Use when an attack targeting a villain is declared to ready this card.
It seems to me that both abilities have the same trigger so I could ready the card for 1 thread and then exhaust it to get 1 black die.
Sadly I can only use an ability once per timing instance. I would have liked those three black dice.