Acara
To play this, you need a Dark Neopet. When a Hero starts a contest in an arena without a Villain, if this card is in your hand, you may put it into that arena. If you do, the contest continues against this Villain instead. This Villain gets +5 to all stats against Heroes. When this Villain loses a contest, untap all its rivals.
Dr. Sloth has paid me to make sure that his plan is carried out perfectly. Believe me, he pays very well.