Shellac is an American post-hardcore band from Chicago, Illinois, composed of Steve Albini (guitar and vocals), Bob Weston (bass guitar and vocals) and Todd Trainer (drums and vocals) and formed in 1992. Their music genre has been classified as post-hardcore and noise rock but they describe themselves as a "minimalist rock trio."

At Action Park is the first full-length record by Shellac, released in 1994. The title is unrelated to the infamous New Jersey theme park, Action Park, which closed in 1996 due to numerous fatalities. The drummer, Todd Trainer, came up with the title of the fictional park because it sounded cool.
The album received highly positive reviews on release. Greg Kot wrote that the "music is still punishing in the extreme, with melody subservient to groove and dynamics, and the human voice just another instrument in a maelstrom", going on to write that "Albini uses his guitar more for color and texture rather than as a lead instrument, while bassist Bob Weston and drummer Todd Trainer create a vicious spin-cycle groove, punctuated by thrilling ebbs and leaps in volume and tempo" and called the engineering "extraordinary".

Retrospectively, AllMusic's Mark Deming wrote that despite Albini's continued obsession with "sex, violence, and anti-social behavior" from his Big Black days and while "the hard, metallic guitar figures of "Pull the Cup" and "Song of the Minerals" were as uncompromisingly abrasive as ever", the album revealed "a band more musically intelligent and imaginative" than his former band. Sputnikmusic called the album "abrasive, arty, nasty, noisy, innovative and unique" going on to call Shellac "proof that there is still massive scope for experimentation and carving out new sounds with a standard guitar, bass, drums lineup in the indie-rock format

In 2012, Fact ranked it the 18th best album of the 1990s, calling it "brilliantly angular [...] Combining Minutemen-esque grooves that feel like they could last forever with spit-riddled, sneering vocals and a storming rhythm section, there are few albums that sound as simultaneously doomed and driven as At Action Park