On this page of our guide to RAGE 2 we have described the Hot Potato silver trophy. This achievement is awarded for reflecting the enemy grenade. On the site you will find tips on how to prepare yourself to unlock this trophy and how to reflect the attack.
You can't achieve this without proper training, as the main character doesn't have the ability to reflect grenades thrown by enemies.
Complete the Blackout story mission. One of the rewards for completing this mission is the access to Kill & Destroy projects tree. The absolute minimum is the acquisition of Grenade Tennis, which allows to reflect grenades when they're in air. We recommend to purchase a second project - a Smash Grenade Tennis. It allows reflecting grenades even when they have landed (before explosion). It will make it very easy for you to get the trophy.
Attack enemies anywhere until you encounter some thug throwing a grenade. Grenades can be easily noticed cause they leave behind a red trail.
If you only have the Grenade Tennis ability, then the grenade needs to bounce before it even lands. But if you have purchased Smash Tennis Grenade as we have recommended above, it is enough to run up to the place where the grenade landed.
In both cases, the grenade can be repelled by pressing the melee button (pressing the right analog knob on the console pads). The trophy is unlocked regardless enemy's death.