Lamprey

This serpentine fish has a horrific circular mouth filled with hooklike teeth.

Lamprey CR 1/3

XP 135
N Tiny animal (aquatic)
Init +2; Senses low-light vision; Perception +1

AC 15, touch 14, flat-footed 13 (+2 Dex, +1 natural, +2 size)
hp 6 (1d8+2)

Fort +4, Ref +4, Will +1

Speed swim 30 ft.
Melee bite +4 (1d4–3 plus attach)
Space 2-1/2 ft.; Reach 0 ft.
Special Attacks blood drain (1 Str damage)

Str 4, Dex 14, Con 14, Int 1, Wis 12, Cha 2
Base Atk +0; CMB +0; CMD 7
Feats Weapon Finesse
Skills Stealth +14, Swim +5

Environment temperate oceans
Organization solitary, pair, or school (3–12)
Treasure none

A lamprey is a tiny jawless fish with a funnel-shaped sucking mouth that contains numerous razor-sharp teeth, which it uses to cut through skin and bore into the flesh of its victims to suck their blood. Lampreys are often found on larger fish in the ocean where they are engaged in symbiotic relationships.

Lampreys can reach a length of up to 4 feet and weigh up to 5 pounds.

Pathfinder Roleplaying Game Ultimate Wilderness © 2017, Paizo Inc.; Authors: Alexander Augunas, John Bennett, Robert Brookes, John Compton, Dan Dillon, Steven T. Helt, Thurston Hillman, Eric Hindley, Mikko Kallio, Jason Keeley, Isabelle Lee, Jason Nelson, Stephen Radney-MacFarland, Alex Riggs, David N. Ross, David Schwartz, Mark Seifter, Jeffery Swank, and Linda Zayas-Palmer.