In the first book, Robert Muldoon used a Customly-Modified Rocket Launcher when he tranquilized the Tyrannosaurus rex. Three had been made at the request of Muldoon, but only one was allowed on the island, stored in a metal vault in the Visitor Center Garage. Muldoon had the foresight to put the launcher into one of two gas-powered jeeps early Friday afternoon, prior to the InGen Incident. Dennis Nedry, following his theft of dinosaur embryos, takes the jeep along with the launcher, preventing Muldoon from neutralizing the Rexy until Saturday morning when it is found. Apparently, it's shoulder mounted, with a battery-operated laser sight. It's Tranq-shells appear like gray canisters with Large, finger-thick needles.