A "28 giant cracker" is a firework, often called a wala cracker or garland cracker, that consists of 28 smaller explosive shells (or "bijili") tied together in a bundle. When lit, it produces a rapid, continuous sequence of 28 loud, crackling sounds and some light or sparks, creating a spectacular, albeit brief, burst of entertainment. These are common during festivals like Diwali in India, designed for ground-based sound and visual effects.