[0.86] Air elementals can knock units out of the tactical grid.
from 
Elemental Forums
Elemental Forums
Basically I had my sovereign soloing an air elemental. I ran into a corner to maximize the space between it and me and it eventually knocked me back out of the grid. I could still cast but could not move to engage it in hand to hand. Not sure exactly what skill/spell it used to do the knockback.
