Wild Shape (Su)
Source: Advanced Player's Guide, p. 99
A cave druid gains this ability at 6th level, except that her effective druid level for this ability is equal to her druid level – 2. She cannot use wild shape to adopt a plant form. At 10th level, the cave druid can assume the form of a Small or Medium ooze as if using beast shape III, and at 12th level that of a Tiny or Large ooze as if using beast shape IV (treating the ooze as if it were a magical beast without a natural armor bonus). When in ooze form, the cave druid has no discernible anatomy and is immune to poison, sneak attacks, and critical hits.