Treachery

Treachery is an epic warlock spell card, from the Knights of the Frozen Throne set.

Known bugs

 * When you use Treachery to give your opponent an Alarm-o-Bot, its effect will not activate at the start of your opponent's next turn, but rather one turn later.

Strategy
The main purpose of this card is to give a minion with a negative Deathrattle, end-of-turn, or triggered effect to the opponent and force them to suffer its effect instead. Some of the cards that make good use of Treachery include:
 * Doomsayer: Clears the board for 5 Mana. While it won't give you a tempo shift like Doomsayer normally would, it counters Deathrattles that only activate on the opponent's turn, like Skelemancer.
 * Ticking Abomination: Heavily damages the enemy board. This effect lacks a true one-turn combo (barring an inefficient Bloodbloom + Blastcrystal Potion combo), so it will require a board setup.
 * Keening Banshee: Could be used to force the enemy to lose cards from their deck, or make unfavorable trades.
 * Howlfiend: Makes the opponent discard their hand. Can be combined with Defile or Dark Skies to empty out the opponent's hand.
 * Bittertide Hydra: Similar concept as above, but with damage instead. This combo costs 2 more mana, so you will need to set up your board first to exploit it.
 * Unlicensed Apothecary: Can be used with Leeroy Jenkins to deal 10 extra damage, although this combo can't be played in a single turn. Can be combined with Diseased Vulture and Curse of Rafaam to deal up to 25 damage.
 * Rattling Rascal: Trades a 2/2 for a 5/5, giving you two 5/5s at the cost of giving the opponent a 2/2.
 * Fel Reaver: With a large number of low-cost cards, this combo can be used to mill most or all of the opponent's deck.
 * Master Chest: You get the reward from its Deathrattle instead of your opponent.
 * Octosari: Very likely mills the opponent. Devastating if you can also give them Baron Rivendare.
 * Wrathguard or Soulbound Ashtongue: Allows minion-only damage to affect the opponent's hero. This can be very powerful with multiple Mo'arg Artificers in play.
 * Harbinger Celestia: Can be used together with any of the above (like one that costs more than 4, or a legendary) to Treachery both of them, doubling the impact (but it is harder too).

Trivia

 * The artwork for this card comes from the World of Warcraft Trading Card Game "Throne of the Tides" series, for the card Hunrik Blackiron.

Patch changes

 * Added.