From Hearthstone: Heroes of Warcraft Wiki
Gain control of an enemy minion with 3 or less Attack until end of turn.
You can rationalize it all you want, it's still a mean thing to do.
 How to get
|Golden Shadow Madness||800||100|
- Minions possessed by Shadow Madness are returned at the end of the turn, after any effects that state "at the end of your turn".
- Shadow Madness is a very tactical card, capable of being used to great effect. Unlike permanent mind control effects like Mind Control, minions that are affected by this card are not exhausted, but can be used by the priest that same turn.
- One common tactic is to use the controlled minion to attack another, hopefully destroying both minions. This effectively grants removal for two minions with only one card.
- One less common tactic is to control a valuable minion, and before the end of your turn play a return card such as Ancient Brewmaster, placing it into your hand. This allows the priest to permanently seize control of the minion, as long as they are happy to spend the mana necessary to summon it. Ideally, use the minion to deal damage before returning it to your hand, as any damage taken by it will be cancelled when it leaves the battlefield.
- Deathrattle effects of the controlled minion will trigger for your benefit if the target dies attacking. This includes Harvest Golem, Leper Gnome and Loot Hoarder.
- Can also be very useful for removing a powerful taunt minion in order to allow your minions to directly attack the enemy hero.
- As with all mind control effects, any abilities or events that occur while the minion is controlled will treat the controlling player as the minion's owner. This includes deathrattles and other card text effects.