n huge animal 

Perception +14; no hearing, scent (imprecise) 60 feet

Skills Athletics +19

Str +7 Dex -1 Con +7 Int -5 Wis +2 Cha -4

AC  25; Fort +21, Ref +11, Will +14

HP 165; Weaknesses salt 5

Speed 20 feet, climb 15 feet

Melee [>] radula +21 (reach 15 feet), Damage 2d10+10 slashing plus mucus

Melee [>] foot +21 (reach 10 feet), Damage 2d8+10 bludgeoning plus mucus

Ranged [>] disgorged mucus +17 (brutal, range increment 50 feet, splash), Damage 3d6 acid damage plus mucus and 1d6 acid splash damage

Malleable The giant slug can fit through tight spaces as if it were a Large creature. While Squeezing, it can move at its full Speed. It can Squeeze through spaces that typically fit only a Medium creature, but it does so at the usual Speed for Squeezing.

Mucus Any creature hit by the giant slug or that moves into its mucus trail is coated in sticky, caustic mucus. It takes 1d4 persistent acid damage and takes a –5-foot status penalty to its Speeds while the damage persists.

Mucus Trail Any square the giant slug moves into is coated in mucus. These spaces are difficult terrain, and any creature that moves into one or ends its turn in one is subjected to the slug's mucus. After an hour, the mucus dries and the area is no longer difficult terrain.

Trample [>>>] Large or smaller, foot, DC 27

Bestiary 2, page 244.