Gas droid

Gas droid was a modification of an assassin robot, that was used to neutralise a large group of rioting citizens. It was developed in the very first years ofClone Wars by the order of future Moff Iv'Iurius to make the country dwellers leave their houses and move to the cities (thus making an easier way of controlling all of them).

One droid could kill instantly a group up to 100 people with a poisonous gas, that it would release into an energy shield sphere that a gas droid could form around itself.

The Katrabi family is believed to have been killed during the attacks of one such droid.

Fortunately the droid production was stopped approximately in 13 BBY.