Entity: Unseen Lizardfolk

Source Character Guide pg. 57 ^2.0

You can change your skin color to blend in with your surroundings, making minor shifts with a single action and dramatic changes over the course of an hour. When you're in an area where your coloration is roughly similar to the environment (for instance, forest green in a forest), you can use the minor, single action application of this ability to make localized changes that help you blend into your surroundings, gaining a +2 circumstance bonus to Stealth checks until your surroundings change in coloration or pattern.