The Droideka Lego Star Wars Minifigure is a Destroyer droid that rolls into battle, uncurls, and encases themselves in a semi-transparent energy field, and then deploy built-in blasters to deadly effect.
The original Droideka appears in Star Wars Lego Sets Republic Gunship 7163 and Jedi Defence I 7203.
The Droideka Minifigure was redesigned in 2007 and is available in the Star Wars Lego Trade Federation MTT Set 7662.
2011 saw the 3rd version of the Droideka Minifigure which appears in the Star Wars Lego Set Naboo Fighter 7877.
