Chakroad

The Chakroads are portals which Bowser uses to travel through in the game, Mario & Luigi: Bowser's Inside Story. Bowser first encounters a Chakroad in the Cavi Cape after hearing a strange voice, which explains that they can take him to places through his mind. Although Chakroads can take Bowser through many places throughout the overworld, they can only take him to places where he has been to and found the Chakroad in. Chakroads can be found under things such as rocks that Bowser can simply punch to break. It is later found out that Chakroads are owned by Chakron.

Since the portals are always hidden under things that only Bowser can unveil, the Mario Bros. cannot use the portals.