During the Clone Wars, the separatists would go to any lengths possible to take out their worst enemies and most dangerous targets. As a result, the separatists did what they do best, and created a brand new, terrifying droid model which had the ability to shapeshift to the appearance of other droid models and even humans. This droid would then be used as a highly elite assassin droid, to eliminate enemies of the confederacy.
The CQ-3.80 Multi Spectrum disguise suite was an advanced holo projection technology, which was capable of completely disgusting a droid’s exterior, even as it was moving and extending it’s limbs. The technology was capable of giving a simple GONK droid, the appearance of a deadly B-2 Battle droid, but that wouldn’t be too convincing because of the large difference in movement.
Scarily however, this technology was capable of giving a droid the appearance of any humanoid also, meaning it could impersonate anyone it had previously laid it’s eyes upon… Although this would be slightly less convincing, it was incredibly useful for espionage missions and break ins, and tricked almost every single human they came across.
Knowing this, the separatists, and later even the empire combined the technology with a TC-SC infiltration droid, which was a fourth degree Assassin and Espionage droid, that went for about 15,000 credits on the black market.