Like a Dragon: Infinite Wealth - 83 - Substory 36: Relics from the Past

In Chapter 13, the western part of Aloha Beach has a peculiar display as two excavators are proudly sitting on the sand. Turns out they're here to celebrate a company's history, and they're fueled up... and there's no cover on the battery slots... and there's no way to control them which would make it a disaster if they were to be activated... You see where this is going.

After the cutscene, take a few steps and you'll come across a familiar face, which should bring back memories of the previous games, also involving an excavator... After that scene, leave and return to proceed, and Yasuda will show up again with some very peculiar fish that'll be a great part of his aquarium. A pair of electric catfish...

And of course, it happens, the fish are sent flying away and neatly fit in the open battery slots, powering up the excavators for you to fight!
Lam-chan and Lun-chan's Excavators are thankfully only at level 31 which should be more than manageable at this stage of the game. They're both weak to Fire while resisting Electricity, so burn'em up to make things go faster!

A bunch of people will have enjoyed the show, some people... less so. But Yasuda will reward you with a pair of Gorgeous Rubber Gloves, the Housekeeper's Job EXP accessory, and the substory will end!