Doctor Robotnik’s Waterspout and Depth Charge Machine (スクリューモービル Sukuryū Mōbiru?, lit. "Screw Mobile"), alternatively spelled as Doctor Robotnik’s Waterspout & Depth Charge Machine, is a boss in Sonic the Hedgehog 3, that the player has to fought at the end of Hydrocity Zone Act 2. It takes eight hits to be defeated. The battle takes place in a flat arena with water just deep enough to cover Sonic, threatening to drown him.