got the newly added "Tectonic Bulwark" shield and tried its special ability "Tectonic Shift". the "stinking mud" effect it applies to the target tile and surrounding tiles makes the units inside it completely immobile. if i remember correctly, the stinking mud in FE (I think that was the combo spell Earth 2 & Water 2 or something) only reduced movement speed, but didn't make everyone inside immobile. not sure if it's a bug or intended that way, but i find it rather annoying that way, since that also means your champion is now also stuck in the area (unless you use another teleport ability [i.e. thunderstike, blink, etc]) to get out of it. i mean, the item is already  hands down the best tank item in the game, but it's a shame that the special move is barely worth using.