The mahamba is a freshwater cousin of the mosasaur, a large prehistoric marine reptile. The mahamba can reach a length of 50 feet. The aboriginals simply call it Nkoli and sometimes compare this terror to the nguna-monene, a sizeable lizard-like monster, even if the creatures are quite different.
Although overly voracious, this cunning aquatic monstrosity seems to know when to give up and swim away, a rare quality amongst the biggest predators.
This reptilian creature has a fish-like body but the head is similar to that of a crocodile. This behemoth can assuredly swallow an entire dugout canoe in one gulp.
Mahamba CR 12
   XP 19,200
   N Colossal animal (aquatic)
   Init +4; Senses low-light vision; Perception +10
Defense
   AC 20, touch 2, flat-footed 20 (+18 natural, –8 size)
   hp 242 (17d8+170)
   Fort +22, Ref +10, Will +7
Offense
   Speed 20 ft.; swim 40 ft.
   Melee bite +19 (4d6+15/19–20 plus grab), and tail slap +14 (4d6+8)
   Space 30 ft.; Reach 20 ft.
Special Attacks devour rafts and canoes, fast swallow, swallow whole (4d6+15, AC 19, 24 hp)
Statistics
   Str 40, Dex 11, Con 31, Int 2, Wis 15, Cha 5
   Base Atk +12; CMB +35; CMD 45 (can’t be tripped)
   Feats Great Fortitude, Greater Sunder, Improved Critical, Improved Great Fortitude, Improved Initiative, Improved Overrun, Improved Sunder, Lunge, Power Attack
   Skills Perception +10, Swim +30
   SQ amphibious
Ecology
   Environment warm aquatic (freshwater)
   Organization solitary, pair, or school (3–6)
   Treasure incidental
Special Abilities
Devour Rafts and Canoes (Ex) A mahamba can swallow completely a vessel and its entire crew if the ship is of size Large or smaller.