The Plasma Probe was a low-tech hover drone that was used by various factions before, during, and after the Great Galactic War

Great Galactic War Event Great Galactic War (3681BBY - 3653BBY)

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It was designed to be thrown towards an enemy and hover over the area for 15 seconds, ejecting superheated plasma to ignite all flammable objects within a 30m radius.
Although it could cause more damage than an incendiary bombs or grenades, it could be completely avoided by the enemy if they ran out of the probe's spray range quickly enough - because the probe's limited logical capabilities prevented it from following the target.