uncommon ne gargantuan construct mindless troop zombie 

Variant shambler troop (Bestiary 3 302)

Perception +14; darkvision

Str +6 Dex +0 Con +4 Int -5 Wis +2 Cha -2

Slow A shambler horde is permanently slowed 1 and can't use reactions.

AC  25; Fort +21, Ref +16, Will +17

HP 240 (16 squares); Thresholds 160 (12 squares), 80 (8 squares); Immunities death effects, disease, mental, paralyzed, poison, unconscious; Weaknesses area damage 10, slashing 10, splash damage 5

Troop Defenses

Speed 20 feet; troop movement

Form Up [>]

Grave Tide The shambler troop is less organized than most troops. It can move into other creatures' spaces, and other creatures can move into its spaces. Its spaces are difficult terrain to other creatures.

Shambling Onslaught [>] to [>>] Frequency once per round; Effect The shamblers lash out at any enemies in their squares or within 5 feet (DC 25 basic Reflex save). The damage depends on the number of actions. [>] 3d6+9 bludgeoning damage [>>] 3d8+13 bludgeoning damage

Troop Movement Whenever a troop Strides, it first Forms Up as a free action to condense into a 20-foot-by-20-foot area (minus any missing squares), then moves up to its Speed. This works just like a Gargantuan creature moving; for instance, if any square of the troop enters difficult terrain, the extra movement cost applies to the whole troop.

OoA3, page 31.