The Portable Watermelon Cooler refers to a real Japanese invention—a motorized, climate-controlled stroller designed specifically to transport a single watermelon. Images of the device went viral online as people marveled at its absurdity and the high level of engineering for such a niche purpose. In the meme world, it serves as a metaphor for being overly protective of something specific, useless, or eccentric. It is commonly used to represent how people handle their mental health, obscure hobbies, or fragile belongings with an unnecessary but relatable level of care.