A Generator (ジェネレーター, Generator) is an object introduced in the Subspace Emissary.
Generators appear in the Subspace Emissary. They are dark purple portals about the size of Bowser, and their function is to produce enemies, only a specific type for each Generator, until they get destroyed. There is a set limit on the number of enemies on the screen at any given time, so if the player gets rid of one, it simply spawns another. A Generator can spawn up to 23 enemies: if the player can defeat them all the Generator will simply stop working, but it will not disappear.
Unlike every other enemy in the game (including Jyks), there is no health bar display for a Generator: because of this, there is no way to know how much of a beating it can take. This is mainly because they are treated as stage elements, not enemies.
Generators reappear with their Brawl function. They usually spawn Mites, but can occasionally spawn other enemies like Skuttlers. They disappear after spawning a certain number of enemies, but they yield bonuses if they are destroyed before then.