When Yanma suddenly beats its wings, all the glass in a nearby bakery shatters. Zachary immediately recalls Yanma back to its Poké Ball, disappointed that his Pokémon has caused damage yet again. The baker carries Zachary off to see his dad, so Ash’s group follow. Later, Mr. Evans, Zach’s dad and glass-maker, makes Zach apologize to the baker, Mr. Strussel. Mr. Strussel says Zach should release Yanma, and Mr. Evans sadly agrees. Later, at a playground, Zach recounts how he first met Yanma to Ash and the group. According to him, there was a severe rainstorm a few months ago. Zach was helping his dad on the way back from delivering glass to another town when they spotted a Yanma lying on the ground. The two of them took it home and took care of it. However, as soon as it got better, Yanma broke all the glass in Mr. Evens’ workshop. Zach decided to train Yanma but to no avail.
(Source: Bulbapedia)