Shambling Mounds are creatures composed of mass of earth, leaves and other natural residue. They are capable of drawing power from the earth to cast spells.
Caster - Unit can cast spells during battle.
Summon - Unit was summoned and belongs to another world.
Construct - Unit is immune to Mind and Death effects, poison, critical hits, Gaze attacks and Positive and Negative energy. They cannot be raised from the dead.