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Deals damage and has a 30% chance to lower the target's accuracy by one stage.
Mud Bomb has little competitive use, as it is weak and inaccurate. The chance to lower accuracy is also not a big draw, since doing so is an unreliable tactic. Mud Bomb is eclipsed by Earth Power, which is both more powerful and more accurate.
Earth Power is a more powerful option.
Mirror Shot is a Steel-type equivalent.
Octazooka is a Water-type equivalent.