The name of the mission is a portmanteau on "Imp," the zombies that one tries to stop the party for, and "Insomnia," the inability to sleep, making a joke on how one is stopping the loud plant party so that the Imps can sleep in this mission.
The Imps cannot sleep due to the plants having a disco party. Z-Mech 11011-3 makes the player stop the party by destroying all the stereos. When the player destroys the stereos, the player must defeat a Champion Disco Chomper. Afterwards, the mission is complete.
- There are plants such as Weeds and Kernel Corns that will attack you when trying to destroy all the stereos. Vanquish every plant first, then proceed to destroy the stereos.
- Do not go into the party zone unless you want to be full on attacked by all plants at the party. Instead, try to use an ability that will kill the Kernel Corn, or at least a few of the Weeds, such as the Foot Soldier's ZPG, or the All-Star's Imp Punt .
- Disco Chomper is a legendary variant, though do not let its rarity fool you. It will not activate its ability, since it needs to digest zombies. Thus, staying on a rooftop will make it easy to beat.
The goal is straightforward, and the only classes that gain an advantage are those that can get on top a roof like Foot Soldiers.