I have yet to see reports of any class specific achievements for Rash of the Itch King, so in the same spirit as the clever Negative Achievements, I present to you my entirely egotistical ideas for mage related achievements.
ORLY? Spellsteal Blessing of Protection from a Paladin while the Paladin is attempting to heal himself.
WTF LAG! Spellsteal Ice Block or Divine Protection from a mage or paladin, respectively.
Sheep Fetish. Polymorph yourself.
BBQ. Deal damage to a player of the same level equal to, or greater than, half of their total hitpoints with one spell.
Wait for it… Fall 500 yards without dying.
You can’t save them now. Kill an enemy player while you have another player polymorphed.
Too close. Ice Block when you have less than 1% of your total health remaining.
Yeah, that was a mistake. Ice Block while carrying the flag in Warsong Gulch, allowing the alliance/horde to return it.
It’s OK, you tried. Cap a flag in Arathi Basin or Alterac Valley while you have an enemy player polymorphed.
Jinx! Counterspell another mage at exactly the same time they counterspell you.
Ice Lance Spree. Land 5 killing blows in under 20 seconds.
WTB Hearth. Ice Block with at least ten hostile players targeting you.
Just some ideas I’m tossing around.
Feel free… no, I heartily encourage everyone else to come up with stuff. The more, the merrier.