After Ness receives the final melody, he finds himself in a strange new place.
Go east from where you start. You can talk to your sister Tracy to use Escargo Express. You can talk to Mom to rest.
Go south to find a shop. You can get Earth Pendants and Magic Puddings there. The puddings restore 40PP. Earth Pendants give you resistance to Fire, Freeze, and Flash. The Sea Pendant is stronger than the Earth Pendant, however.
If you go west from this area, you find an area with some snowmen. There is a gift box on the west side of the snowman area that contains a PSI Caramel.
There is a house to the north. There are Flying Men in this house. You can have a Flying Man join you as an ally in battle, much like Picky, Pokey, and your dog at the beginning of the game. You can't control the Flying Man or heal him, but he will help automatically in battle. If the Flying Man dies, his grave will appear in front of the Flying Man house, and you can talk to another Flying Man to have him join you. They are not infinite: if all of the Flying Men die, you can't get another Flying Man.
East of the Flying Man house, you find a red area where you will encounter monsters. If you are near level 99, run away from all the battles. You will get a special level up at the end of Magicant, but only if you are not already at level 99.
From the start of the red area, go east to find a gift box that contains a Bag of Dragonite. You can talk to the Ness there to get a Baseball Cap, but it does not provide much protection, so you can sell it or drop it, or give it to Escargo Express.
From there, go back the way you came until you can go north. Keep going north when the path splits and you will find a gift box that contains a Goddess Band. Then go back the way you came, and go east when you can. Follow the path from there and you will pass by a gift box that contains a Magicant Bat. Continue following the path from there and you will find a gift box that contains a Magic Tart. Then continue on the path and check on the metal tentacle at the end to warp to the Sea of Eden.
Sea of Eden
You will encounter Krakens in the water. They DO NOT have the Gutsy Bat. As long as you have equipped protection from fire, you can defeat the Krakens fairly easily with physical attacks. The Krakens do not respawn, so after you defeat them, they are gone for good.
Go east from the metal tentacle, then go northwest when you can. You will find the final boss of Magicant in the northwest part of the Sea of Eden. Make sure to equip the Sea Pendant if you have it. If not, use the Night Pendant or Star Pendant. Otherwise, equip the Earth Pendant (go buy one from the shop in Magicant if you don't have one.)
The statue starts the battle with a PSI Shield α. Start the battle by using a Bag of Dragonite/Bomb/Super Bomb if you have any. The statue can put up a Shield β, which reflects physical attacks, so you want to use a strong physical attack before the statue can put up the reflecting shield. If the statue has not used Shield β yet, use weak PSI attacks until its PSI Shield α goes away. You can use strong PSI attacks at that point, but be sure to conserve some PP for healing if you don't have any healing foods with you. It might be better to stick with physical attacks unless the statue has a Shield β in place.
Be sure to use Lifeup whenever the statue uses a strong attack, and keep your HP high so you will have time to heal up if you take mortal damage.