The Invasion block is the sixth block, consisting of the large expansion Invasion () and the two small expansions Planeshift () and Apocalypse (). The block came out in 2000-2001.
This block was centered around the idea of multiple colors working in synergy, with an inordinately large amount of gold cards. Many mono-colored cards in the block also played to the multicolor theme, either in bonuses granted by other colors or off-color activation costs. In this way, Invasion was a precursor of the later Ravnica block.
Keywords introduced in this block: Kicker.
Themes present throughout the block included multicolor strategy, tribal themes, Domain cards, Gating cards, and Kavu creatures.
There are two four-card mega cycles in the Invasion block, each started in Invasion with two cards and finished in Apocalypse with two more.
Magic Player Rewards provided some cardboard tokens for the block. However, because Magic Online needs to represent all the tokens in the game, art needs to be created for even the most insignificant tokens. For those, Magic Online is the only place it appears.  
On the development codenames for the Invasion block, MTG.com columnist Mark Rosewater writes:
|| Invasion block codenames were cities with Chinese names. I believe this theme was picked by Mike Elliott because it fit our recent hard-to-spell kick. The original choices were actually so complicated that we had to change them.