Ptah's Shifting Sands can be used to transport allied or enemy units from one location on the map to another. All allied units are affected, but not every enemy unit in the area will be moved.

To summon the sandstorm, left click on the Shifting Sands icon.  Targeting the sand storm requires two left clicks, the first is near the units you wish to transport, the second is where you want those units transported.  You must have <link="topic:line of sight">line of sight</link> to both clicked areas.  A good use for sandstorm is to shift an invading army out of your town or to transport quickly past some defenses for a surprise attack. 