Planar Chaos is a Magic: The Gathering expansion set released in 2004. It is part of the Time Spiral block and features a unique theme of alternate realities and timelines. The set introduces new mechanics and reprints cards with altered colors and abilities, reflecting the idea of chaos in the multiverse. The set contains 165 cards and is known for its innovative design, including the Morph mechanic and the concept of "color-shifting," where cards are printed in different colors than their original versions. This expansion explores the consequences of manipulating time and space within the game's lore.