A zombie is permanently Slowed 1 and can't use reactions.
AC 15; Fort +9, Ref +5, Will +5
HP 60, void healing; Immunities bleed, death effects, disease, paralyzed, poison, unconscious; Weaknesses vitality 10, slashing 10
Tangling Kelp
Trigger A creature attempts a melee attack against a zombie grindylow with a bludgeoning or slashing weapon
Effect The creature must succeed at a DC 15 Reflex saving throw or become tangled in the kelp that surrounds the zombie grindylow, giving the creature a -10 circumstance penalty to its Speeds until it spends a manipulate action to remove the kelp.
Void Healing
A creature with void healing draws health from void energy rather than vitality energy. It is damaged by vitality damage and is not healed by vitality healing effects. It does not take void damage, and it is healed by void effects that heal undead.
When a grindylow Grabs a creature larger than itself, it attaches to that creature. The grabbed creature is not Immobilized, but if it moves, the grindylow moves with it.
If the creature is Medium or smaller, it takes a –5-foot status penalty to its Speeds while the grindylow is attached. The grindylow is Off-Guard while it is attached to a creature.
Effect: Clinging Suckers
Jet(move)
The grindylow moves up to 60 feet in a straight line through the water without triggering reactions. It can use this ability while grabbing a creature.
Grab
Requirements The monster's last action was a successful Strike that lists Grab in its damage entry, or the monster has a creature Grabbed or Restrained
Effect If used after a Strike, the monster attempts to Grapple the creature using the body part it attacked with. This attempt neither applies nor counts toward the creature's multiple attack penalty.
The monster can instead use Grab and choose one creature it's grabbing or restraining with an appendage that has Grab to automatically extend that condition to the end of the monster's next turn.
Pathfinder Society Scenario #2-06: The Crashing WaveOGL