uncommon n medium mindless ooze 

Perception +6; motion sense [object Object] feet, no vision

Skills Athletics +9, Stealth +5 (+7 in areas of rusty objects)

Str +4 Dex -4 Con +3 Int -5 Wis +1 Cha -5

Motion Sense As yeast ooze.

AC  11; Fort +10, Ref +3, Will +6

HP 80; Immunities critical hits, mental, precision, unconscious, visual; Weaknesses electricity 5; Resistances metal 5

Corrode Weapon [R] Trigger The rust ooze is hit with a metal weapon; Effect The rust ooze deals 2d6 acid damage to the item, ignoring its Hardness.

Metal Resistance A rust ooze has resistance 5 to metal weapons.

Speed 15 feet, swim 30 feet

Melee [>] pseudopod +11, Damage 1d6+5 bludgeoning plus rust and tetanus (Gamemastery Guide 118)

Rust When a rust ooze critically succeeds at a pseudopod Strike, it deals 2d6 acid damage to a metal item the target is wearing or holding, ignoring the item's Hardness. If a creature uses the Shield Block reaction with a metal shield against a rust ooze's pseudopod attack, the shield is automatically broken, but no other item is rusted.

OoA1, page 87.