SFS Standard Excavating Tentacles [one-action] Feat 9

Source Galactic Ancestries pg. 21
Your reinforced tentacles wrap together to burrow through the ground. You gain a burrow Speed of 15 feet for as long as your tentacles are wrapped together, and then you Burrow. You take a -10-foot status penalty to your land and fly Speeds until you unwrap your tentacles as a free action.

Traits

Barathu:A creature with this trait is a member of the barathu ancestry. Barathu are a floating, jellyfish-like ancestry who rewrite their own genetic code at will. An ability with this trait can be used or selected only by barathus.