An The-Dark-Heart Drones (DC Animated Universe)

The Dark Heart was a highly advanced alien construct capable of endlessly recreating itself via the use of nanotechnology.
Powers: Enhanced Physical Attributes and Matter Assimilation.
The primary force of the Dark Heart are insect-like drones programmed to seek out all organic and non-organic matter. Their nano-assembler sub-routines then convert the matter into a liquid material fed back into the main Dark Heart. A small amount of larger drones are created to assist the smaller ones. Once the Atom overloaded the Heart, the drones were automatically deactivated. General Eiling gathered all the drones and remains, allegedly intended for destruction. 
In reality, the drones were handed over to Project Cadmus. The technicians were unable to reactivate the drones and stored them in a vault located in a Cadmus facility near the White House in Washington DC. During their partnership, Lex Luthor convinced Brainiac to seek out these drones. After assimilating their abilities, Brainiac and Luthor converted every drone into a new form that would make the two villains one unique persona.
* This form was soon destroyed by the Flash using lightspeed vibrations.