Wisp Fetchling
Source Pathfinder Lost Omens Ancestry Guide
Your ancestors' exposure to the Shadow Plane wrought great physical changes. Your hair or skin sometimes appears insubstantial, and you're slighter and more agile than other fetchlings. You're Small instead of Medium. You gain the trained proficiency rank in Acrobatics, the Quick Squeeze skill feat, and a +1 circumstance bonus to Acrobatics checks to [/act tumble-through]. If you would automatically become trained in Acrobatics (from your background or class, for example), you instead become trained in a skill of your choice.