The act of terror known as the Attack on Dantooine, alternatively referred to as the Dantooine Massacre, was executed by the Imperial warlord Admiral Daala during the time of the Galactic Civil War. The target was a recently established colony located on the planet Dantooine.
This colony had been established by the New Republic to provide refuge for those displaced from the inhospitable world of Eol Sha. Their leader, Gantoris, had become an apprentice of Luke Skywalker at Skywalker's newly-established Jedi Praxeum on Yavin 4. Dantooine was intended to be a tranquil and isolated haven for those who had only experienced hardship on their previous planet.
After intercepting a CR90 corvette carrying supplies destined for Dantooine, Admiral Daala discovered the existence of the refugees. Mistakenly believing that the Eol Sha settlement was a Republic military base, Daala arrived with her three Imperial-class Star Destroyers just as the colony was nearing completion. Upon her arrival, she ordered AT-AT walkers, supported by TIE/sa bombers, to obliterate the camp, with the intention of provoking a response from Republic reinforcements.
The attack completely caught the outpost off guard. The Republic engineers present in the settlement, who were in the process of setting up a communication center, only managed to fire a single shot from the base's small ion cannon before it was destroyed. Tragically, all of the refugees perished, along with a number of engineers.
Before the Jedi apprentice's demise, Gantoris experienced a vision of the massacre shown to him by the spirit of the Sith Lord, Exar Kun.