Osomatsu-kun: Suika no Hoshi kara Konnichiwa zansu!

Visitors from a watermelon-shaped planet arrive on Earth with a deceptively simple invasion plan. Their watermelons spread quickly through town, and Iyami and Chibita see only a chance to make money by selling the unusual fruit at outrageous prices.

The joke turns dangerous when anyone who eats the alien watermelon begins transforming into a watermelon person. With the invasion spreading, Dekapan races to develop a cure while the sextuplets and the town's usual troublemakers are dragged into a battle against an enemy that looks far more refreshing than it really is.