ce small aberration amphibious 

Perception +5; darkvision

Languages Aquan

Skills Athletics +5, Stealth +7, Survival +5

Str +1 Dex +3 Con +2 Int -1 Wis +3 Cha +0

Items spear

AC  15; Fort +6, Ref +7, Will +5

HP 14

Attack of Opportunity [R] A grindylow gains 1 extra reaction at the start of each of its turns that it can use only to make an Attack of Opportunity with a tentacle. It can't use more than one Attack of Opportunity triggered by the same choice.

Speed 10 feet, swim 25 feet

Melee [>] bite +7 (finesse), Damage 1d6+1 piercing

Melee [>] tentacle +7 (agile, finesse, trip), Damage 1d4+1 bludgeoning plus Grab

Melee [>] spear +5, Damage 1d6+1 piercing

Ranged [>] spear +7 (thrown 20 feet), Damage 1d6+1 piercing

Clinging Suckers 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 flat-footed while it is attached to a creature.

Jet [>>] (move) The grindylow moves up to 60 feet in a straight line through the water without triggering reactions.

Bestiary 2, page 138.