Sonic & All-Stars Racing Transformed

Easy method

Start up your game with 3 controllers plugged it and go to CUSTOM GAME then select LOCAL.

Next go to the second game mode called BATTLE ARENA and from here select NEON DOCKS.

Place the 2 IDLE characters next to each other then drive around till you get the HOT ROD weapon. Use the weapon when next to both players and the achievement will pop.

There is a time limit but you will not need the whole time.

For this Achievement you need to set off the Hot Rod weapon in range of 2 other racers. The only annoying part for this is getting the weapon at the right time, as the race progresses the cars get more and more split up and are rarely in close range of each other.

If you don't get this through natural play I'd suggest picking a simple level like Ocean View and keep restarting it until you get a Hot Rod right at the start. Try and stay around 4th to 6th, puts you right in the middle of the action and increases your chance for better weapons.

Once you get the Weapon and are in position press A to start the boosting effect of the weapon, when you're close to two racers press A again to set the blast off and if you hit them both the achievement will pop within 2 or 3 seconds. This is easiest in a car but to my knowledge is possible in all vehicle types.

Alternatively if you own 3 controllers you can set up two extra to stay idle in Battle Arena Mode, use pads 2 and 3 to put them close together, then just keep getting items as Player 1 until you get the Hot Rod. Then simply approach them and double tap A to ignite and detonate your Hot Rod.