Making one more unique to the invoker class.

Name: miasma

Giving them roughly the same spell but a different name and origin for the spell.

From the Plane of Air, a spell that lets the caster actually become mist-like when confronted by a door or gate. Though the spell has the same duration as "Pass Door" there are no signs that the spell is in use: (translucent). In theory it would be a spell called upon when the caster comes upon a barrier he/she wishes to cross.

Received at level 24 after perfecting "wind wall".

There would be a slight delay in reforming on the opposite side of the barrier, depending on how thin the caster would have to spread him/herself. ie.. running through a gate would take less time to reform than between the cracks of a thick iron door. The delay would lessen as the spell nears perfection.

It couldn't be used to avoid bashing though.