Memory Alpha
Memory Alpha
"Once unleashed, the unit is invincible. The perfect killing system."
"Too perfect… you poor fools, your own creation destroyed you."

An Echo Papa 607 drone

The Echo Papa 607 was an advanced weapon system developed by the arms merchants of Minos.

Intended to be a complete weapon of war, the Echo Papa 607 was able to automatically send out small drones to gather intelligence, take prisoners, and mount attacks. The main advantage of the system was its progressive adaptability; data on enemy equipment and tactics was returned to the parent system each time a drone was destroyed, and a new drone was manufactured which improved on the previous model, countering the enemy's abilities. The process of analyzing each encounter and replacing a drone took only twelve minutes and through this method the drones quickly became impossible to stop.

The Enterprise-D firing on a cloaked starship-sized drone

The drones were able to monitor and disrupt enemy communications, as well as project interactive holographic illusions of individuals familiar to its enemy in order to gather intelligence. To capture prisoners for interrogation, a drone could encase a target in a force field that kept it in stasis. The drones were armed with directed energy weapons and could be modified to include deflector shields for protection, and cloaking devices for stealth. They were able to attack both ground troops and starships. A single cloaked drone was able to cause heavy damage to the USS Enterprise-D.

The Echo Papa command system

A still active Echo Papa 607 unit was present underground on Minos in 2364, long after the Minosian civilization had been wiped out. It destroyed the USS Drake and nearly destroyed the Enterprise-D before Captain Jean-Luc Picard realized the attack was a demonstration for a potential customer. The system shut down after he agreed to "buy" the device from the planet's automated merchant. From his interaction with the holographic merchant, Picard surmised that the Minosians developed the Echo Papa 607 but lost control of it and were destroyed by their own weapon's demonstration. Data also determined that the weapon system had been used by the belligerents of the Ersalrope Wars as an intelligence gathering device. (TNG: "The Arsenal of Freedom")

The miniature of the Echo Papa 607 was built by visual effects supervisor Dan Curry, using an old L'eggs pantyhose container and a discarded shampoo bottle. (Star Trek Encyclopedia (4th ed., vol. 1, p. 228); TNG Season 1 DVD special feature "Memorable Missions")
On its use in production, he elaborated, "Regarding the model robot built for the TNG episode "Arsenal of Freedom" – the Echo Papa 607, I decided to hand animate the model for its levitation sequences instead of using motion control which was the norm. As a result the model has a more fluid natural randomness to its movement. My thirty years of Tai-Chi allowed me to move the model in a way that kept its motion believable, threatening, and saved the expense of days of motion control photography." [1]
Presumably, "Echo Papa" is usage of a phonetic alphabet.