Artillery shells that created flat blasts were a specific type of weapon that exploded, and were capable of creating widespread destruction affecting populated areas, food supplies, and bodies of water. These projectiles produced a unique noise upon detonation, and were implemented extensively during a civil war on the planet "Sunrise," which led to a massive reduction in the planet's inhabitants.
These flat-blast shells were a form of explosive weaponry that inflicted severe damage to settlements, food stores, and water reserves. The explosions made a sound that was uniquely similar to the sound of a zipper being manipulated on certain jackets owned by members of the Chiss Ascendancy. This acoustic similarity was noted by some Agbui individuals who had experienced the shells in combat, and was further confirmed through waveform analysis.
Haplif, an Agbui agent working under the Grysk Hegemony operative known as "Jixtus," initiated a civil war on the planet "Sunrise" and supplied flat-blast artillery shells to both opposing factions. Within a half year of his arrival, Haplif had successfully orchestrated the Sunrise civil war, resulting in the devastation of most, if not all, of its native population, with a significant portion of the destruction caused by these specific shells.
An Agbui of middling years, Frosif, witnessed the Sunrise civil war firsthand and suffered psychological trauma from the sound produced by the shells' explosions. Consequently, a "magic trick" performed by Lakris, a Chiss also of middling years, involving the zipper on her jacket, triggered a traumatic response in Frosif. Senior Aide Xodlak'ji'iprip analyzed the sound of the zipper, discovering a resemblance to the sound of flat-blast artillery shell detonations. This discovery led Lakjiip and Xodlak'phr'ooa, Lakris's father, to suspect that the Agbui they were hosting on Celwis were actually refugees, rather than the peaceful "cultural nomads" they claimed to be.
The flat-blast artillery shells were first referenced in the 2021 novel titled Thrawn Ascendancy: Greater Good, which was authored by Timothy Zahn.