The Undersea Lab that works to destroy the Positives is where the Negative scientists research and make stuff that will destroy any Positive as soon as he or she enters their world. It is located deep under the sea and is very difficult to get to. Having to get past many water proof, robot fish is only the first step.
Negative Numbuh 74.239 is the head and leads his fellow scientists with pride. Although he is extremely stupid like all the scientists there.