Destroy J-Lab! is a mission in Grand Theft Auto 2 given to Claude Speed by Elmo of the Loonies. The mission is available from the right of the two yellow Loony phones in Fruitbat of the Downtown District.
The Yakuza have created a drug to cure the insane, and are using it on the Loonies. They would like to stay in insanity, and so Elmo hires Claude to blow up the Yakuza's J-Lab, where the stuff is being developed. Claude does this and ends up destroying the place and project permanently.
Elmo: Yo, Jumbo, it's Elmo. New Yakuza drugs are making the insane sane - which is bad news for us Loonies. Pick up explosives from the University and use them to wreak havoc at J-Lab.
(Claude drives to the explosives cache and takes the stuff. He then heads for the J-Lab)
Elmo: Take out the short-ass Yakuza guard and plant explosives in his place. FAST!
Yakuza Guard: "No-one trespasses in J-Lab!
Elmo: Cool shootin', Jumbo! Plant the explosives in his place.
(Claude plants the explosives by the machines)
Elmo: Climb the stairs and watch the fun, Jumbo. J-Lab is about to close permanently!
(As soon as Claude climbs upstairs, the bombs blow)
Elmo: Oh yes, baby, watch it blow! Flaming narcotics are my favorite firework.
Elmo: "The J-Lab is history and the Loonies are safe in insanity. You are one real cool cat, Jumbo. Maybe we do business some other day. For now, here's $40,000."
The reward for completing the mission is $40,000.