Area 2: Farmland
Mukumuku's Gift
» Exit your farmhouse
» 6:00 am to 12:00 pm, Winter season, sunny day
» Mukumuku 100+ FP
» Have nothing in your green Rucksack slot
As you exit your farmhouse, Mukumuku will greet you at the front door. He will say something in Muku-ese (which of course no one can understand), and present you with a Large Fish. Then he will leave.
The fish he gives you is just a plain, ordinary Large Fish.
English version confirmed by starryfrawg