Great card to let your fellow heroes go to their Alter-ego. It doesn't specify it needs to be an attack boost. You can trigger while Villain schemes to prevent up to 3 threat. Plus 3+1 damage, that's a great value.
Attack. Preparation. Skill.
Hero Interrupt (attack): When a boost card is turned faceup, discard Attacrobatics → cancel the boost icons on that card. Deal 1 damage to the villain for each boost icon canceled this way.
Black Widow #6. Black Widow #7-8.
It's a Hero Interrupt card, so you can't use it in Alter-Ego form to prevent threat. — Thebof · 1
That's not what OP stated. They just highlighted the fact that, though it is an attack card, it can be used when the villain thwarts, and can help when teammates are in alter-ego (an example of when the villain would thwart). — Feral9 · 8