Mandroid M-99 is working as Mandark's most trusted droid. He knows that after Spawns take DNA samples from heroes and fuse them with the dangerous green Fusion Matter, a Fusion is created with DNA and Fusion matter. The Fusion creates a Nano after it is destroyed. Once the Fusion is destroyed, it separates into two pieces of Fusion Matter, thus creating a Nano. Only Dexter, Ben, Mandark, Gwen, Edd, Numbuh 4, Professor Utonium, and Mandroid M-99 know this.