At the end of the second cave of chapter 6, you battle the two statues, Twin Sumocho.

How to Defeat Twin Sumocho

Twin Sumocho will sometimes spit fireballs at you, so be prepared to jump to avoid them. Throw Shurikens to the north, and press the attack button to split them so that they hit both of the statues. You can jump on the southwest tile to make double hearts appear, and you can jump on the southeast tile to make more Shuriken appear. Keep throwing Shuriken and splitting them to hit Twin Sumocho until they are destroyed.

Moving On

Don't jump north after the battle! You have to jump west or east first. Go through the north door, then go north to exit the cave. The path is straightforward, so just keep going. Eventually, you will find a person. Talk to the person and there will be a cutscene. You can say Yes if you want the story repeated.

Afterward, go north and continue to the end of the passageway. Go up the stairs, then go north. You will proceed to Chapter 7: Alien Spaceship.