Giga Wallace is a story mode boss monster of Dokapon DX.
Think of it as if Overlord Rico had its true form in the 3-2-1 version.
As with other Wallaces, they have anti-banish, meaning that they cannot be instantly killed. He has debug+, a battle magic when he can reduce your hp to one, and recover all of his HP. If you have Bounce, you can reflect that attack.
If Giga Wallace fails to counter when you use a weapon skill that can confuse or curse it, he'll have a chance to strike or hurt himself.
This is the final boss if more than 40 weeks have passed.
The difference between this and Overlord Rico is that this monster doesn't have auto-counter, and his stats are randomized depending on how many weeks you passed.