PvP: Enchanters Conoundrum. I've been using this skill in RA and I've been fairly impressed with it. If you leave it on a monk, their Guardian is bait and it takes more time to cast the precious skills to keep them ticking. But, the fun comes when you Shatter their enchants, and then smash them with Shatter Delusions! 180 damage, armour ignoring spike

PvE: Arcane Conoundrum. This skill slows caster-mobs really well. I love it.