This "Rank Up Synthesis Evolution" Item

The "Rank Up Synthesis Evolution" item, "Tropical Juice," obtainable by completely clearing the "Sealed Boss Trial" in this collaboration event. Why is this sealed boss Suika Nyan (Watermelon Nyan)? Suika Nyan is one of the "Fruit Nyans" with 100% fruit juice, and like the others such as "Melon Nyan," "Ichigo Nyan" (Strawberry Nyan), "Mikan Nyan" (Mandarin Nyan), "Kiwi Nyan," and "Budo Nyan" (Grape Nyan), they are naturally targeted by the "Food Guardians" due to their nature as food-based Yo-kai. Every year, when their season arrives, their lives are targeted by Yo-kai from all over the Yo-kai World as part of the "Fruit Nyan Hunt." However, I'd like you to think about something for a moment. Aren't you curious about the source of the fruit juice that is likely used in Tropical Juice? Speaking of which, in this event's story, we didn't see any of the other Fruit Nyans besides Suika Nyan... Could it be!?