The Mmm is an insectile hive-mind, a single creature that controls the billions of smaller creatures (drones) that make up Mmm. Visible Mmm-drones look like insects.
The homeworld of Mmm is a small but fertile world with a lot of atmosphere and water, probably due to Mmm micro-managing the whole planet. But Mmm also has 70 000 sentient nodes and drones spread around the galaxy. Mmm drones have to eat and they eat plants.
Mmm is an active participant in galactic politics and many races fear it. It is very powerful and can probably take over and control the galaxy if it wanted to and were aware of this fact. Mmm is however pacifist even if drones take part in Scout teams and work as Patrol officers.
Sources: GURPS Aliens