While looking for the Slimming Mushroom, Happy tells Lucy that Natsu usually eats a poisonous mushroom called "Laughing Bamboo", as Natsu munches on different kinds of mushrooms as they speak. Natsu then suddenly grows a mushroom on the top of his head, surprising Lucy but disappointing Happy since it wasn't the Laughing Bamboo he previously mentioned. Suddenly, Lucy finds the mushroom they were looking for, but Happy reminds her that it might be the look-alike mushroom that the request sheet warned them about.
Natsu proposes that Lucy should taste the mushroom, but Happy takes it and tasted it before Lucy can. At first, Happy seems to be poisoned but suddenly grows a mushroom on the top of his head, too. Happy becomes depressed since he believes that it isn't funny anymore when the joke is played a second time, and becomes even more depressed when Natsu's mushroom grows even bigger, remarking that Natsu gets all of the good jokes.