Giant Lake Octopus CR 10
During Combat The octopus stays in the water, attacking enemies on shore with its tentacles. It tries to grab as many victims as it can and then pull them into the water to bite and poison before it feeds on them.
Morale The octopus flees back into the waters of the lake when reduced to 50 hit points or fewer.
Str 28, Dex 15, Con 21, Int 2, Wis 12, Cha 3
Base Atk +11; CMB +22 (+26 grapple); CMD 34 (can’t be tripped)
Feats Combat Reflexes, Improved Critical (bite), Improved Initiative, Iron Will, Lightning Reflexes, MultiattackB, Power Attack, Skill Focus (Stealth), Stealthy
Skills Escape Artist +19, Perception +9, Stealth +15, Swim +17; Racial Modifiers +10 Escape Artist, +8 Stealth
A giant lake octopus can jet backward once per round as a full-round action, at a speed of 200 feet. It must move in a straight line while jetting, and does not provoke attacks of opportunity when it does so.
Pathfinder Adventure Path #46: Wake of the Watcher