Master Impersonator: Man-Beast can use Shape Change. If an opposing character has been KO'd by Man-Beast this game, this Shape Change succeeds on a roll of 4-6.

Emotional Corruption: When a character takes damage from Man-Beast's attack, after actions resolve Man-Beast can use Mind Control targeting that character as a free action.

Do I have to use Emotional Corruption? What if Man-Beast attacks a character that has a point value over 100 points... maybe I don't want to take damage for using Mind Control on that character!
You do have to use Emotional Corruption (game effects can't be turned off), but you never have to give a character an action if you don't want to do so. If you don't want to risk taking damage for Mind Controlling the target, simply don't give Man-Beast that free action to use Mind Control.