The phrase comes from everyday Tagalog slang, where ang bilis means how fast or so fast and gagi is a mild, joking swear word often used among friends. Clips built around the line spread through Filipino social media edits, gaming highlights and short form video, where creators needed a quick verbal reaction to anything moving unexpectedly fast. Its appeal has lasted because it is short, expressive and easy to drop over unrelated footage, letting one surprised voiceover explain the joke without extra context or setup for viewers watching quickly online.