n huge animal 

Perception +15; low-light vision, scent (imprecise) 60 feet

Skills Athletics +18, Stealth +15 (+17 in undergrowth)

Str +7 Dex +2 Con +4 Int -4 Wis +2 Cha -2

AC  25; Fort +17, Ref +15, Will +13

HP 125

Speed 25 feet, swim 25 feet

Megalania Venom (poison) Saving Throw DC 25 Fortitude; Maximum Duration 6 rounds; Stage 1 1d6 poison damage and clumsy 1 (1 round); Stage 2 2d6 poison damage, clumsy 2, and flat-footed (1 round); Stage 3 2d6 poison damage, clumsy 3, and flat-footed (1 round)

Swallow Whole (attack) Large, 2d10+7 bludgeoning, Rupture 16.

Bestiary 2, page 168.