I give you koolasuchus, who recently had his first real time in the spotlight in the 5th part of Walking With Dinosaurs.

Koolasuchus
Large Animal
Hit Dice: 3d8+24 (37 hp)
Initiative: +3 (+3 Dex)
Speed: 5 ft. (1 square), swim 30 ft. (6 squares)
Armor Class: 12 (-1 size, +3 Dex), touch 12, flat-footed 9
Base Attack/Grapple: +2/+15
Attack: Bite +10 melee (1d8 +9)
Full Attack: Bite +10 melee (1d8 +9)
Space/Reach: 10 ft./5 ft.
Special Attacks: Improved grab, swallow whole
Special Qualities: Low-light vision
Saves: Fort +11, Ref +6, Will +2
Abilities: Str 29, Dex 17, Con 26, Int 2, Wis 13, Cha 7
Skills: Concentration +9, Hide -1, Listen +1, Spot +1, Survival +5, Swim +10
Feats: Die Hard,Endurance
Environment: Cold forest streams
Organization: Solitary
Challenge Rating: 3
Treasure: Standard
Alignment: Always neutral
Advancement: 4-6 HD (Large); 7-9 HD (Huge)
Level Adjustment: -
Koolasuchus is the cold-weather version of eogyrinus. It lives alone, doesn't meet with others of its kind unless to mate, and has an appetite to match its big head.
Combat
Improved Grab (Ex): If a koolasuchus hits with a bite attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity. No initial touch attack is required. Improved grab works only against opponents medium size or smaller. The koolasuchus has the option to conduct the grapple normally, or simply use its bite to hold the opponent. If it chooses to do the latter, it takes a –20 penalty on grapple checks, but is not considered grappled itself; the koolasuchus does not lose its Dexterity bonus to AC and still threatens an area. A successful hold does not deal any extra damage. Each successful grapple check it makes during successive rounds automatically deals the 1d8 damage of the bite. When a koolasuchus gets a hold after an improved grab attack, it pulls the opponent into its space. This act does not provoke attacks of opportunity. It can even move (possibly carrying away the opponent), provided it can drag the opponent’s weight.
Swallow Whole (Ex): If a koolasuchus begins its turn with an opponent held in its mouth (see Improved Grab), it can attempt a new grapple check (as though attempting to pin the opponent). If it succeeds, it swallows its prey, and the opponent takes bite damage. The opponent must be medium size or smaller. A creature in the koolasuchus' gullet has 1d6 acid damage done to it each round. A swallowed creature is considered to be grappled, while the koolasuchus is not. A swallowed creature can try to cut its way free with any light slashing or piercing weapon (the amount of cutting damage required to get free is 15 points), or it can just try to escape the grapple. The Armor Class of the interior of a koolasuchus is 10+1/2 its natural armor bonus, with no modifiers for size or Dexterity. If the swallowed creature escapes the grapple, success puts it back in the koolasuchus’ mouth, where it may be bitten or swallowed again.