Arakni, Web of Deceit (HNT002 M Cold foil)

Your attacks with stealth that are attacking a marked hero get +1 and "When this hits, this gets go again."
At the beginning of your end phase, if an opponent is marked, you become a random Agent of Chaos. (Your doesn't change.)
Chaos Assassin Hero - Young

Marvel
From the Flesh and Blood TCG set The Hunted