What’s an Adult Swim bump? Here’s a definition from the Adult Swim Fandom wiki:
The Bumpers, or “Bumps” for short, which are shown before and after each commercial break, were originally shots of senior citizens swimming and doing random pool-related activities in public pools. The lifeguard is often heard talking through a megaphone and saying things such as “Adult Swim, all kids out of the pool!”, and announcing the forthcoming TV show. The logo was, basically, “ADULT SWIM” written in large red/or yellow capital letters (or a alternate version of the logo featured “adult swim” in red lowercase letters in a black circle with a yellow penumbra). On Saturdays for the Action Block starting February 23, 2002, the shows were announced by a computer generated voice and the bumps featured clips of the shows. Adult Swim’s main theme music was “D-Code”, performed by Melbourne artist Dust Devil. The song was a remix of “Mambo Gallego” by Tito Puente, Sr.
Artists like Flying Lotus and Nujabes featured heavily in the bumps and they opened the door to a range of other artists such as Thelonious Martin.