The Geonosians are commanded by Poggle the Lesser .They look alot like bugs. You can unlock poggle in lego star wars 3. He is located somwhere in the jail cells. you could try making up your own combination . For example count dooku with poggle. geonosians have different kinds of guns. some shoot giant balls of ion energy and some have normal blasters if you want to see geonosians in an arena. rent attack of the clones on dvd or watch the clone wars season 2