1x15 - The Melancholy of Haruhi-chan Suzumiya

Using the balloons she got from Kyon, Yuki makes Ryoko a living balloon dog, although its creation is a little horrifying. Whilst having fun with it, Ryoko walks into another trap laid by Yuki, with assistance from the dog, who suddenly talks and calls himself Kimidori. Ryoko is attached to balloons that Yuki filled with hydrogen, which causes the balloons to detonate in a large explosion when one of the balloons is heated by a ceiling light.