n huge animal 

Perception +9; darkvision

Skills Acrobatics +8, Athletics +10, Stealth +8

Str +4 Dex +2 Con +4 Int -5 Wis +2 Cha -4

AC  19; Fort +11, Ref +9, Will +7

HP 45

Attack of Opportunity [R] Tail only.

Speed 30 feet, climb 30 feet

Melee [>] mandibles +11 (reach 10 feet), Damage 1d10+6 piercing plus whiptail centipede venom

Melee [>] tail +11 (agile, reach 15 feet), Damage 1d6+6 bludgeoning plus Knockdown

Undulate [>] The giant whiptail centipede Strides or Steps. During this movement, it can pass through spaces as narrow as 5 feet without Squeezing.

Whiptail Centipede Venom (poison) Saving Throw DC 19 Fortitude; Maximum Duration 6 rounds; Stage 1 1d10 poison damage and clumsy 1 (1 round); Stage 2 2d10 poison damage and clumsy 1 (1 round); Stage 3 2d10 poison damage and clumsy 2 (1 round)

Bestiary 2, page 50.