Fortnite has a new weapon in Chapter 3 Season 2. The Anvil Rocket Launcher is here, and it is designed to take out vehicles, especially tanks. Rather than being a fire and forget weapon, the Anvil Rocket Launcher can lock on to vehicles and track them.
To use the Anvil Rocket Launcher, just aim down sights at a vehicle. There will be a bar at the bottom of the screen that will slowly fill up, and when it is full the weapon is locked on. After that, you can fire and then run for cover as the rocket shoots up into the air, coming back down again directly on top of the vehicle.
Anvil Rocket Launchers can be found in regular and Rare Chests, in Seven Supply and IO Chests, in Supply Drops, and from sharks. Exactly how many rockets it takes to finish off any vehicle will vary, but the Anvil is a very easy way for players on foot to cause a lot of problems for the tanks.