Entity: Cavern Kobold

Source Advanced Player's Guide pg. 13 ^2.0

You hatched into a warren among narrow tunnels and countless kin. Your body is flexible. When Climbing rock walls, stalactites, and other natural stone features, you move at half your Speed on a success and at full Speed on a critical success (and you move at full Speed on a success if you have Quick Climb). This doesn't affect you if you're using a climb Speed. If you roll a success on an Acrobatics check to Squeeze, you get a critical success instead.