Thought bomb

A thought bomb was a Dark Side weapon typically created by several Sith channeling the Dark Side into one single focus, creating a single, volatile physical explosive that when detonated unleashed the full, raw power of the Dark on anyone caught within its blast radius. It was able to be detonated via a simple handclap or a snap of one's fingers. It became infamous after both the Scourge of Katarr by Darth Nihilus in the Dark Wars of the 3900s BBY and the Seventh Battle of Ruusan of 1000 BBY, when Darth Bane convinced the Brotherhood of Darkness to create and detonate one of these devices on the planet, wiping out all life on it save for Bane himself and some of the Jedi Lord Hoth's Army of Light.

Some Sith, like Darth Nihilus, were so powerful on their own that they were able to relatively quickly create a miniaturized, football-shaped thought bomb in the palm of their hand and direct most of its energy towards the enemy, effectively sparing the Sith and his forces from its destructive power. However, any disruption of the Dark Side could cause this version of the bomb to painfully misfire, as what happened to Nihilus when Hisone Amakasu damaged his mask during the Second Battle of Malachor V.

Behind the Scenes
Nihilus' thought bomb was partly inspired by the Infinity Gauntlet featured in the Marvel Universe.