Space hero, gadget guru, robot blaster, Ratchet has had plenty of experience piloting fast vehicles in his adventures, and this Lombax puts those talents to good use on the race tracks of Jak X.”— Ratchet character description, Jak X: Combat Racing
Ratchet and Clank are the main protagonists of the Ratchet & Clank series. Created by Insomniac Games, the characters have made cameos in the Jak and Daxter series, and have appeared in other games alongside Jak and Daxter. Likewise, Jak and Daxter have made similar cameos in Ratchet & Clank games.
The commonness of cross-cameos are the result of Naughty Dog and Insomniac Games' close early relationship. This dates back to their development of Crash Bandicoot and Spyro the Dragon, respectively. The two studios began sharing technology and improvements, and having developed similar titles, shared much of their fanbases in common. Homages to, references to, and cameos within the two series followed, as well as a non-canon cross-over game, PlayStation Move Heroes. Furthermore, Ratchet and Clank served as story rivals to Jak and Daxter in the game PlayStation All-Stars Battle Royale.
In Jak 3, Ratchet and Clank appear as civilian targets in separate Ratchet and Clank gun courses (as well as Tyhrranoids, an enemy race from Up Your Arsenal, appearing as enemy targets). The duo returns in Jak X: Combat Racing, with Ratchet appearing as an unlockable racer with his own description, and Clank appearing on a pennant for purchase from the secrets shop for 40,000 Precursor orbs. To unlock Ratchet, a save file from Ratchet: Deadlocked must be present on the memory card.
Collectible masks resembling Ratchet and Clank appear in Daxter, the former found in the transit system during the mission "Take care of bugs in transit system", and the latter found in the first tanker mission, "Collect 30 gems from the tanker".
Lastly, Daxter references Clank in the Jak and Daxter Trilogy movie, saying, "As you can see Jak and I can take out any robot that boots up, even cute talking ones that like to 'clank' around. Yeah, that's right, I said it!"