Illusions & Grouping (Cancel Magic)
 

Casting either Illusion Ogre or Troll gives you the Slam Ability not sure if this is intended.

After leaving a group you are still able to cast Strip Enchantment type spells on them still to remove there buffs, this seems to persist until either you or the previous person(s) formally in your group leaves the zone or re-logs.

After googling this looks to be intended behavior.