The following material is Open Game Content from the Menace Manual SRD
Improved Grab (Ex): To use this ability, the tyrannosaur must hit an opponent two or more size categories smaller than itself with its bite attack. If it gets a hold, it shakes the grabbed opponent back and forth, automatically dealing bite damage each round. Once the opponent stops resisting, the tyrannosaur attempts to swallow on its next turn.
Scent (Ex): This ability allows a tyrannosaur to detect approaching enemies, sniff out hidden foes, and track by sense of smell.
Swallow Whole (Ex): If a tyrannosaur begins its turn with an opponent two or more size categories smaller than itself held in its mouth, it can attempt a new grapple check as though trying to pin the opponent. If it succeeds, it swallows its opponent, automatically dealing bite damage. Once inside the tyrannosaur, the opponent takes bludgeoning damage equal to the tyrannosaur’s bite attack plus 1d6 points of acid damage per round from the monster’s gizzard. A successful grapple check allows the swallowed creature to climb out of the gizzard and return to the tyrannosaur’s maw, where another successful grapple check is needed to get free. Alternatively, the swallowed creature can attack from inside the gizzard using claws or a Small or Tiny slashing weapon. Dealing at least 25 points of damage to the gizzard (Defense 20) in this way creates an opening large enough to permit escape. Once the creature exits, the tyrannosaur must make a successful Fortitude save (DC 20) or die, whether or not the full amount of damage was dealt with a single blow. A Huge tyrannosaur’s gizzard can hold 2 Medium-size, 8 Small, 32 Tiny, or 128 Diminutive or smaller opponents.
Tyrannosaur: CR 11; Huge animal; HD 20d8+80; hp 170; Mas 19; Init +1; Spd 40 ft.; Defense 14, touch 9, flat-footed 13 (–2 size, +1 Dex, +5 natural); BAB +15; Grap +32; Atk +22 melee (4d6+13, bite); Full Atk +22 melee (4d6+13, bite); FS 10 ft. by 10 ft.; Reach 15 ft.; SQ improved grab, scent, swallow whole; AL none; SV Fort +16, Ref +13, Will +8; AP 0; Rep +0; Str 28, Dex 12, Con 19, Int 2, Wis 15, Cha 10.
Skills: Listen +11, Spot +11.
Advancement: 21–36 HD (Gargantuan); 37–54 HD (Colossal).