|"Only a moron challenges a waterbender to a water war ..."|
|— Katara gloating about her victory.|
"Water War" is a comic book that takes place in Book One: Water, originally released by Nick Mag Presents: Avatar: The Last Airbender on September 12, 2006, and later released by Dark Horse Comics in Avatar: The Last Airbender — The Lost Adventures. Select magazine sellers put this issue of Nick Magazine on sale three days early, making "Water War" available for purchase on September 9.
Katara decides that she should put two young children in their place when they soak innocent citizens at an Earth Kingdom market.
Katara is browsing through a market in an Earth Kingdom village when two children begin dropping water balloons on civilians from the second story of a nearby building. The soaked citizens walk away dripping, unable to retaliate. Upon seeing this, Katara decides to reverse the situation.
When they try to drop water balloons on her, she waterbends them back at the children. The kids, having realized what was coming, hide behind a door, avoiding the balloons. However, Katara anticipates this and bends a barrel-full of water, sending it up to soak them with a number of citizens looking on. Once they have been thoroughly doused, townspeople cheer as Katara gloats about her victory against the "morons" who challenged her, a waterbender, to a water war, as Sokka raises a water balloon of his own to throw at his sister from behind.
- Main article: Transcript:Water War
- In "Bee Calm", Katara was without her necklace, but in "Water War", she has it back, meaning that this comic takes place after "Bato of the Water Tribe".
- Avatar: The Last Airbender — The Lost Adventures categorizes this comic under its Book One section, but Katara and Sokka are wearing their clothes from Book Two: Earth.
- "Water War" was released in the first issue of Nick Mag Presents: Avatar: The Last Airbender along with "Sokka the Avatar" and "Bee Calm".