Proteans are serpentine outsiders of pure chaos. They have the following traits.

• Blindsense (distance varies by protean type).
• Immunity to acid.
• Resistance to electricity 10 and sonic 10.
• Constrict and grab as special attacks.
• Supernatural flight.
• Freedom of Movement (Su) A protean has continuous freedom of movement, as per the spell.
• Amorphous Anatomy (Ex) A protean's vital organs shift and change shape and position constantly. This grants it a 50% chance to ignore additional damage caused by critical hits and sneak attacks, and grants it immunity to polymorph effects (unless the protean is a willing target). A protean automatically recovers from physical blindness or deafness after 1 round by growing new sensory organs to replace those that were compromised.
• Change Shape (Su) A protean's form is not fixed. Once per day as a standard action, a protean may change shape into any Small, Medium, or Large animal, elemental, giant, humanoid, magical beast, monstrous humanoid, ooze, plant, or vermin. A protean can resume its true form as a free action, and when it does so, it gains the effects of a heal spell (CL equal to the protean's HD).