block·bust·er 
(blŏkbŭs′tər)
(blŏkbŭs′tər)n.
1. Something, such as a film or book, that sustains widespread popularity and achieves enormous sales.
2. A large, powerful bomb used especially in air raids on cities.
3. One that engages in the practice of blockbusting.
[Sense 3, from BLOCKBUSTING.]