|This character exists primarily or exclusively within the Sonic Underground continuity.|
Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
The Guardian Bot was a gigantic robot built by Doctor Robotnik that was designed to protecting the dam Robotnik was building in southern Mobius. It was enormous, capable of stepping on trees with its clawed, talon-like feet, and extremely powerful, equipped with strong lasers on both shoulders that could obliterate rocks. It was also impervious to the gun in Sonic the Hedgehog's guitar medallion.
Sonic attacked the Guardian Bot, luring it away from the dam so that Sonia, Manic, the Mountain Folk and Valley Folk could attack the dam. However, the others were prevented from destroying the dam by Sleet and Dingo, who arrived in a flying scorpion-shaped vehicle. Jerod delivered a message from Sonia to Sonic (following the trail of destruction left by the Guardian Bot) to bring the Bot back to the dam. The Bot returned to see Sleet and Dingo firing at Sonia and Manic, who were standing on the dam. Perceiving this as an attack on the dam itself, the Guardian Bot destroyed their vehicle and forced Sleet and Dingo to flee.
The Guardian Bot was destroyed when Manic used a drum solo to crack the dam. Water rushed through, knocking the Guardian Bot over and short-circuiting it. It began to fire wildly, hitting the dam itself with its lasers, then stopped working altogether.
- The Guardian Robot has some similarities, such as deisng and color, to the Transformer Lugnut from the television show Transformers Animated.