Fight Omega Navis
After you earn the first five stars not the mega class chips press RRLRLRLL while holding left to fight omega navis.
A Giga Class Chip
To get the first Giga-Class Chip Jack into the statue on Hades Isle and go through the warp you should find a bug-frag trader. Give him 200 bugfrags to get the Giga chip "Foldrbak."