It is one of the most difficult missions in the game, so do not attempt this mission if you think you may be unprepared or of low level.
Snowy weather regularly freezes your Patapons unless they have resistance to Freeze. Not only is the weather against you, Kacchindonga is very strong. In fact, it is too strong for most to fight without the dodge song. However, through determination, proper equipment and attack pattern study, as well as high knockback, this beast can be defeated even in the Demo version. For most of us, though, its not a fight that you can win for a long time.See "Kacchindonga" for more info on how to bring down this monster of a foe.
Defeating Kacchindonga is one of the post-game challenges. So don't push yourself and just move on for now. Come back later when you're truly prepared.
The good news is, Kacchindonga shares all his attack patterns with Majidonga and Level 10+ Dodonga. The one difference-apart from the dramatic strength difference-is that Kacchindonga's breath attack is ice-based. Instead of Patapons getting ignited, they will freeze instead. Also, Kacchindonga's Roar attack takes twice as long to charge as any other boss attack, giving you time to use PonChaka and ChakaChaka (the only way to minimize the damage of this attack).
You can also use the Tatepon hero to give your troops a god like protection or basically impenetratable. But the Tatepon Hero itself is not an exception to the dinosaur's devour. To dodge this, cancel the action by randomly pressing a drum button and retreat or jump (Pon Pata / Don Don songs) while he prepares for this attack.
When defeated, it drops Lv.1 egg of Kacchindonga Fight. After that, it usually drops Ores and a rare piece of equipment (Giant, Ancient, or Heaven).