Corsac's Convenient Burrow

As an action you can create a 5 foot wide, 5 foot tall tunnel in a space adjacent to you that can extend up to 30 feet away from you in a direction of your choice, including straight up or straight down. This tunnel can go through earth, wood, and unworked stone, but not through worked stone and other constructed materials. On each of your turns for the duration of the spell you can create a new tunnel.

These tunnels do not collapse when your concentration ends, though you can collapse them at any time you want, no action required.