"M" is for "Manaconda"

Manaconda

No. Enc.:  1d4 (1d4)
Alignment:  Neutral
Movement:  105' (35')
      —Swim:  75' (25')
Armor Class:  6
Hit Dice:  11
Attacks:  3 or 1 or 1 (2 fists, 1 bite, or 1 tail-slap, or weapon)
Damage:  2d6 / 2d6 / 1d8, or 3d4, or by weapon
Save:  L9
Morale:  10
Hoard Class:  XVIII
XP:  6,000

The Manaconda are a race of sentient reptiles with hulking, hunchbacked, humanoid torsos and serpentine lower bodies.  They can reach heights of 8'-10' tall and lengths in excess of 20'.  Manacondas dwell in semi-aquatic dens near lakes, rivers, swamps, and submerged ruins.

If both fists successfully strike in the same round, a Manaconda squeezes its target in a bone-breaking hug that does an additional 2d10 damage.  They can also distend their jaws and Swallow targets of human-size or smaller on a biting Attack Roll of 19-20, and those ingested suffer 2d8 damage per round until perishing at the end of 6 rounds.  Manacondas get a +2 bonus to both Attack Rolls and Damage Rolls when using melee weapons. 

Because of their sheer strength and fierce loyalty, they make excellent bodyguards and soldiers.  And Manacondas always speak in the first person.

Mutations:  Aberrant Form (Gills and Lungs), Force Screen (Greater), Thermal Vision