Combat Mounts?

[Passthechips]

Now there was one server I had joined a long time ago that had a special feature. When ever one equipped a certain type of tabard that had no spell on it or anything, one would appear mounted.

You could cast spells and melee while wearing the tabard.

How is this done?

Also another question is it possible to mount an NPC, but when it goes into battle and starts casting spells it does not dismount?

-Thanks for your time.