Ratchet & Clank has a ton of different weapons to add to your arsenal of destruction. Each one has different, unique abilities to handle any enemies and they’re all for the most part bought from the weapons vendor with bolts. The Predator Launcher, however, cannot be bought.
The Predator Launcher is a weapon that has the ability to summon up to four homing missiles. You can do this by holding down the R2 Button and targeting up to four enemies at once. The missiles will launch out and hit the targets (or target if you choose to only unleash hell upon one). In order to get yourself a Predator Launcher, you’ll need to do a bit of side questing. Over on Nebula 634, you’ll have the option to Search the Blarg Warship for Weapons. This is one of the optional objectives on the level, and should you choose to pursue it, you’ll head over to that warship. Scurry through defeating enemies and make it to the end to find your shiny new Predator Launcher. Make sure to haul your butt back, though, because the self-destruct will activate on you and you’ll have a set timer. Don’t use the Predator Launcher in this case, as it’ll take a bit of time to ramp up its attacks. It’s best to just run on through.
Once you’ve made it back, you’re all set with your Predator Launcher in Ratchet & Clank! Congratulations!