Locus

Locus is a nonbasic land type used for cards that depict mana rich observing posts on Mirrodin.

Description
The first card to bear the type was Cloudpost in Mirrodin. It adds for each Locus on the battlefield. Because multiple Loci looked inherently broken, R&D was hesitant to create additional ones. Each new Locus would increase the amount of mana generated by Cloudpost. However, with the printing of Glimmerpost in Scars of Mirrodin deckbuilders were gifted a second playset of Loci and, alongside the landcopying Vesuva from Time Spiral could play up to twelve in one deck. While fine for the Extended format, Cloudpost ended up on the Modern banlist on the second round in September 2015, and has stayed there since.

Storyline
Created by Memnarch to observe his imported creatures, they were later taken over by the Praetors of New Phyrexia.

Trivia

 * Locus is a land type, not a creature type; changelings are not a Locus and you can't use Conspiracy to make a creature a locus.
 * To deliberatly confuse the issue, Locus was used as a creature type on the Mystery Booster test card Swarm of Locus.
 * Locus is also a location on Otaria, created by Ixidor