The Qwark Bot  was found in Ratchet & Clank and Ratchet & Clank: Up Your Arsenal. A cheat could be activated in Deadlocked to make DZ Strikers into Qwarks that fought you as enemies after a certain number of skill points.
Ratchet & Clank
The Qwark bot in this game was a robot copy of Qwark that had a spring for legs and was found in Metropolis, on planet Kerwan. Clank although it was the real Qwark. In Ratchet & Clank, it was set up by Qwark (with the help of Helga) on Kerwan to challenge Ratchet and Clank to complete the 'Captain Qwark Challenge Course' and to meet Qwark's fitness trainer Helga at the end. Clank; however, believed this to be the real Qwark, who had lost his legs fighting evil.
A skill point was acquired by destroying the Qwark Bot with a powerful weapon like the Devastator. If you destroy the Qwark Bot in challenge mode without triggering the cutscene, you do not complete the mission to see it (you can still go onto the challenge course to find the swingshot, though.)
Ratchet & Clank: Up Your Arsenal
The Qwark Bots on Thrann Asteroid were similar to the Qwark bot in Ratchet and Clank, but were security bots that guarded Captain Qwark's secret base on the Thrann Asteroid, heavily armoured and fired rapid blasts of deadly plasma energy at intruders. When they haven't any ammo left, they are were hiding under a little wall charging up, and then started shooting again. They also had a tendency to spout various (apparent) Captain Qwark quotes. Ironically, they were stronger than Captain Qwark himself.
They were armored in green Qwark uniforms with the symbol of the Q-Force. Two hand-mounted plasma cannons were combined with last-resort survival measures (as in crawling legless to slug Ratchet) to make a deadly combination. They moved via a small white, pulsing hoverball where their feet should have been, and had a distinctly robotic voice and look. As more of their armor was exposed, they would remain in position, organized and ready. They used the catchphrase "Watch it, Buddy" whenever an enemy went near them.
They were strong enemies and probably the toughest in the game of their size. They had several layers of armor which allowed for long-term protection, and carried weapons capable of doing significant amounts of damage with a single hit. They also could be teleported into significant areas to serve as reinforcements. Additionally, they had a tendency to attack in groups, making them difficult to defeat at close range. Qwark Bots have been known to survive otherwise fatal attacks, with their armor and hoverball being destroyed, in these cases they will continue to attack Ratchet by themselves across the ground to get close enough to hit him with their arm.
Powerful long-range weapons such as the Flux Rifle were recommended to take these menaces out. Closer up, high-powered weapons such as the Plasma Coil and RY3NO were also used. The Annihilator and Disc Blade Gun were also recommended against these robots.
After activating a cheat in Deadlocked, the DZ strikers you fought now became Qwark bots, using the same weapons they used. This cheat was different to the Qwark bots in the other two games, as they had two legs and didn't talk.