Seryulin, Greater (CR 10)
AC: 22 (+1 Dex, -2 size, +13 natural), touch 9, flat-footed 21
Hit Dice: 21d8+84 (178 hp); DR: 5/piercing or slashing
Fort +13, Ref +10, Will +14
Speed: 50 ft., swim 50 ft.
Space: 15 ft./15 ft.
Base Attack +15; Grapple +32
Attack: Slam +23 melee
Full Attack: 2 slams +23 melee and bite +20 melee
Damage: Slam 2d6+9 plus pain toxin, bite 1d8+4
Special Attacks/Actions: Pain toxin, sticky spray
Abilities: Str 28, Dex 12, Con 18, Int 8, Wis 14, Cha 13
Special Qualities: Amphibious, can't be tripped, resistance to acid 10, slick
Feats: Cleave; Great Fortitude; Improved Initiative; Improved Overrun; Lightning Reflexes; Multiattack; Power Attack; Weapon Focus (slam)
Skills: Escape Artist +9, Listen +14, Spot +14, and Swim +17
Advancement: 22-30 HD (Huge)
Organization: Solitary or clutch (2-4)
Monster Manual III
Sticky Spray (Ex): Once per day, a greater seryulin can use a standard action to expel a 20-foot-radius burst of viscous goo from its body. Any creature in the area becomes entangled and must succeed on a DC 24 Reflex save or become glued to the ground, unable to move. A flying creature is not stuck to the ground, but it must succeed on the save or be unable to fly and fall to the ground. Greater seryulins, as well as their riders, are unaffected by the sticky spray. The save DC is Constitution-based.
Carrying Capacity: A light load for a greater seryulin is up to 2,400 pounds; a medium load, 2,401-4,800 pounds; and a heavy load, 4,801-7,200 pounds. A greater seryulin's carrying capacity is calculated as if it were a quadruped.
The save DC for a greater seryulin's sticky spray (DC 24) adjusted for its greater number of Hit Dice and higher Constitution score.
Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.