This is end-game preparation work available to you after obtaining Risky's Hideout Map. Instead of running straight in to the fight, Mimic will suggest you take some time to form a plan of attack. This plan actually consists of doing some minor fetch quests for the Barons that now appear in Scuttle Town. Each will reward you with a personal piece of Risky's attire (but why they have it is weird enough).Techno Baron
Techno Baron desires his data chip back from the factory. In Mermaid Falls, scene 2, up in the very top of the second screen is a cave lit with torches. You'll need Bat and Spider Dance to traverse this labyrinth of spikes to retrieve the chip.Ammo Baron
Ammo Baron needs some metal to rebuild. Scrap Metal can be found by using the Elephant Stomp on the flowers (similar to how you found the bones in Tassel Town). The locations for the flowers:
Hypno Baron wants to reassemble an army. You might have already come across the Sunken Souls he's wanting, but if not, I will at least highlight where they are. There are 10 in total and once you've acquired one in the world section, you'll see how many are still left. This might require a combination use of Mermaid Dance, Mermaid Bubbles, Crab Dance, and Crab Claw to get to. I'll label which is required for each so you don't end up going after certain ones prematurely with their acronyms (MD, MB, CD, CC).
There are 7 in Mermaid Falls and 3 in Tassel Town. Four out of seven in Mermaid Falls are found in the first second (before the factory) with the remaining three found during the factory segment. As for the ones in Tassel Town, you should find all of them within the first section (exterior, before the tower). All of them, as per their names might suggest, will be within the water.
Squid Baron's simply vain and wants to fill the Gallery up with pictures of himself. He'll have taken down a Velvet Poster from there when you talk to him. With this in hand, head back to the Hypno Baron's Castle. Within the first scene, go straight ahead, and then again to reach Abner, who has claimed the castle for his siblings and himself. However, he wants to get it decorated properly, for which he'll exchange a poster he has for your Velvet Poster. It just so happens that it is a Squid Poster.
After collecting each Baron's item and returning it to them, you'll obtain a Risky-themed reward. Take all four of the items to Mimic to obtain the Magic Polarizer and complete this side-quest (gearing you up for the Good Ending).