The Operator is a unique type of Process that appears as a large white box.
Operators do not move, do not attack, and have little in the way of defenses. Their only purpose is to spawn other types of Process to the battlefield. Each Operator has a limited number of Spawns, with a fixed set of Processes that can appear in that fight. These spawns can produce anything, from Badcells to Fetches to Jerks. For this reason, it is important that Red destroy the Operators first, to make sure that no more Processes can join the fight.
Often, an Operator will be protected by a Cheerleader at the beginning of the fight, making it that much harder to destroy.
Once an Operator has used all its Spawns, it is inert and can do nothing but get destroyed. However, they often have several thousand HP, so they can take quite some time to take down. To destroy an Operator quickly, use powerful attacks like Cull and Flood. Note that Operators have no "face" side, so they cannot be Backstabbed or Shifted. Unmasking will still provide its double damage bonus.