Mugann are weapons created by the Anti-Spiral to suppress the population of Spiral lifeforms and major antagonists in the second half of Tengen Toppa Gurren Lagann.
They are designed to exterminate the Spiral lifeforms of their respective planets once they surpass a specific population limit, in order to prevent the outgrowth of Spiral energy and the Spiral Nemesis from occurring. They attack by firing powerful lasers and possess virtually impenetrable energy shields. Once defeated, they explode and send off explosive cubes of energy.
After the human population of Earth exceeded one million, the Human Extermination System put in place by the Anti-Spiral was triggered, causing Nia Teppelin to be awakened as the Anti-Spiral's messenger and Mugann to be deployed to eradicate all Spiral lifeforms on Earth.
The initial Mugann attacks were fended off by Simon in the Gurren Lagann and the Grapearl squadrons of the human government, but their numbers eventually grew too massive. When the remaining humans attempted to evacuate the planet in the Ark-Gurren to avoid being destroyed when the moon collided with it, the Mugann assaulted the craft to kill all the humans aboard, but the attack was fought off by Simon in the Gurren Lagann, who combined with the Arc Gurren and destroyed the combined Kyo Mugann, ending the Mugann threat on Earth.
- Soldier Class Mugann - Grunt units, appearing in massive numbers. They are colored orange and light red.
- Jokyu-Mugann - Command units, colored green. They command Soldier Class Mugann.
- Kyo-Mugann - A pair of massive Mugann units colored purple and blue. They are capable of splitting off smaller Mugann from them and combining together into an even larger unit.