whizbang

noun3

1. •
   (old-fashioned) A type of firework that made a whiz before exploding.
2. •
   (figurative) Someone or something that holds an explosive amount of success, skill or effectiveness.

   • She [Agatha Christie] has produced a whizzbang surprise which I am unable even to hint at without spoilsporting. — 1967
3. •
   (old-fashioned) A small artillery shell.

   • World War I: Trench Songs, Oxford University Hush, here comes a Whizzbang