Secret: When your opponent plays a minion, summon a copy of it.
"You go first." - Krush'gor the Behemoth, to his pet boar.
 How to get
|Golden Mirror Entity||400||50|
- Mirror Entity only triggers when the opponent plays a minion directly from their hand. Minions summoned by other means (such as Reinforce or Mirror Image) will not trigger Mirror Entity.
- Minions are copied in every detail, including current stats and card text.
- As Mirror Entity minions are not played from the hand, any Battlecries possessed by them will not be activated.
- However, like all secrets, Mirror Entity takes effect after any Battlecries from the triggering minion.
- One example of the above rule can be seen when copying a minion such as Frostwolf Warlord whose Battlecry potentially modifies its own stats. For example, if a Frostwolf Warlord is played alongside 4 other minions, its Battlecry will result in an 8/8 Frostwolf Warlord. If Mirror Entity triggers from that minion, it will produce an 8/8 Frostwolf Warlord, but that minion's Battlecry will not activate. In this way Mirror Entity can copy the consequences of the target minion's Battlecry, but will not activate it for the copy minion. However, if the copy is returned to the player's hand and then played, the Battlecry will activate normally.
- Conversely, this can work to the mage's advantage when Mirror Entity triggers against strong units with negative Battlecry effects, such as King Mukla, Leeroy Jenkins, and many Demon cards, making Mirror Entity a good play early-on against warlocks, who often accept discard effects or self-damage in order to summon powerful, low-cost minions.
- This card is best played in the late game, as it has a higher chance to copy a strong minion then.
- When playing against a mage, this secret can be baited by playing a weak minion before playing any larger ones. If this secret does not trigger, you are safe to play larger minions; if the secret does trigger, it will only copy the weak minion, and you will then be free to play larger ones. Playing a weak minion also may allow you to attack with them, possibly dealing with a Vaporize.
- If playing as a priest against a mage and they cast a secret, summoning a venture co. mercenary may show this card. silencing your own venture co. mercenary will leave them with a card that raises their minions cost by 3 mana.
This spell doesn't seem to have a precise match in Warcraft lore. However, mages are well-known as masters of illusions, able to summon multiple fully-functioning images of themselves to assist in battle or even teaching and spell-casting, such as through the spell Mirror Image.
This card's art may be a reference to Valve's Portal game series. The games feature a "portal gun" capable of opening small wormholes between two locations through which the player and other objects can pass, with one portal appearing light blue and the other orange. The two modes of the portal gun also caused it to glow the colour of the corresponding portal, similar to the mage's hands in this card's art.
 Patch changes
- Patch 18.104.22.16888 (2013-06-22): Now activates when your opponent plays a minion, rather than when an enemy minion attacks.