Gerrothorax

Originally Posted by bhu of the Wizards Community forums. 
On this Thread 

Gerrothorax is a amphibian from the Triassic period about 3.3 ft long, and had a remarkably flattened body. It hid under sand or mud on river and lake bottoms, scanning for prey with its large, upward-facing eyes.

Gerrothorax
Small animal (Aquatic)
Hit Dice	1d8 (4 hp)
Initiative	+0
Speed	20 ft. Swim (4 squares)
Armor Class	12 (+1 Size, +1 Natural), touch 11, flat-footed 11
Base Attack/Grapple	+0/-1
Attack	Bite +0 melee (1d4-1)
Full Attack	Bite +0 melee (1d4-1)
Space/Reach	5 ft./5 ft.
Special Attacks	–
Special Qualities	Low Light Vision
Saves	Fort +2, Ref +2, Will +2
Abilities	Strength 8, Dexterity 10, Constitution 11, Intelligence 1, Wisdom 14, Charisma 4
Skills	Hide +2*, Spot +2, Swim +7
Feats	Weapon Finesse (Bite)
Environment	Warm Aquatic
Organization	Solitary
Challenge Rating	1/2
Treasure	None
Alignment	Always Neutral
Advancement	2 HD (Small)
Level Adjustment	—

Skills Gerrothorax have a +8 racial bonus on Swim checks. It can always choose to take 10 on a Swim check even if distracted or endangered.

*As a full round action a Gerrothorax can cover itself in sand and deris at the bottom of the river giving it a +4 circumstance bonus to its Hide checks.