n huge animal 

Perception +13; tremorsense (imprecise) 60 feet

Skills Athletics +17, Stealth +14

Str +6 Dex +3 Con +5 Int -5 Wis +2 Cha -4

AC  23; Fort +18, Ref +14, Will +11

HP 140; Immunities acid; Weaknesses water 10

Viviparous Birth When killed, an empress bore worm violently expels the young it carries. These young erupt as a bore worm swarm in the empress bore worm's space. In addition, every creature within 20 feet takes 5d10 acid damage (DC 25 basic Reflex save) from the splatter of caustic viscera.

Speed 25 feet, burrow 40 feet

Melee [>] bite +17 (reach 15 feet), Damage 2d6+9 piercing plus 1d6 acid and painful bite

Borer An empress bore worm can leave a tunnel behind itself when it burrows, and it usually does.

Corrosive Wake [>] The empress bore worm Strides, leaving behind dribbles of acid in every square that it passes through. A creature that enters or begins its turn in such a square takes 3d6 acid damage (DC 22 basic Fortitude save). The acid becomes inert after 1 minute.

Painful Bite The bite of an empress bore worm causes excruciating pain. The target must succeed at a DC 25 Fortitude save or become sickened 1 from the pain (sickened 2 on a critical failure).

Bestiary 3, page 37. Expanded in LOIL.