Devour

Devour is a static ability first introduced in Shards of Alara.

Description
Devour is Jund's signature mechanic, and it received cards through the entirety of the Alara block. When a creature with Devour is to enter the battlefield, the player may sacrifice any number of creatures to the devourer to add +1/+1 counters to it.

Devour holds a 6 on the storm scale, and has been quantified as the example of a 6 - the mechanic is narrow, rather unpopular, but flavorful. The specificity of the payoff may have led to the more variable designs of Emerge and Exploit.

After Alara block, Devour returned in the Primordial Hunger deck of Planechase 2012, Commander 2015, Modern Horizons and Commander 2020.

Devour [type]
With Caprichrome, Modern Horizons 2 introduced the keyword variant Devour artifact, that changes the type that can be devoured to artifacts.

Rulings

 * Devour appears only on creature cards.
 * A creature with devour can devour other creatures no matter how it enters the battlefield.
 * You may choose to not sacrifice any creatures.
 * If you cast a creature with devour as a spell, you choose how many and which creatures to devour as part of the resolution of that spell. (It can't be countered at this point.) The same is true of a spell or ability that lets you put a creature with devour onto the battlefield.
 * You may sacrifice only creatures that are already on the battlefield. If a creature with devour and another creature are entering the battlefield under your control at the same time, the creature with devour can't devour that other creature. The creature with devour also can't devour itself.
 * If multiple creatures with devour are entering the battlefield under your control at the same time, you may use each one's devour ability. A creature you already control can be devoured by only one of them, however. (In other words, you can't sacrifice the same creature to satisfy multiple devour abilities.) All creatures devoured this way are sacrificed at the same time.

Plane card that grants Devour

 * Jund (whenever a player casts a black, red, or green creature spell - devour 5)

Trivia

 * Devour was featured as rules card 4 of 5 in the Shards of Alara set.
 * Devouring Hellion has a form of Devour 2 that includes Planeswalkers.