A band of Rajeki space pirates landed on a small planet planning to use their gigantic delta ray cannon to wipe another planet nearby. The only inhabitant of the planet the pirates had landed on was a Watcher and being aware of The Watchers' vow to never interfere in the matters of others, The Rajeki ignored him and attempted to carry out their plan. However the onlooking Watcher melted their cannon with his unspeakable powers and then converted the entire crew into negative beings. He then dispatched them to far away planet where they could do no harm. Wondering why The Watcher had broken his vow, the Rajeki learned the planet they were planning to destroy was the home world of The Watchers thus he was not interfering in the matters of others!
The Rajaks were created by brothers Stan Lee and Larry Lieber and first appeared in "The Watcher's Power!" in 1965.
The Rajaks were referenced in the 2014 film "Guardians of the Galaxy", when Peter Quill was telling Drax the Destroyer about the various women who'd attempted to make his life miserable. One of these women is "A smokin' hot Rajak girl" who stabbed Quill with a fork when he missed watching a sunrise with her.
Marvel's Agents of S.H.I.E.L.D.
In season 5, episode 20, the Rajaks are mentioned as one of the races who comprise the Confederacy.