The Backlash Grenade is a rare and effective human device, developed especially to kill Chimera, and has helped turn the tide of the war in favor of humanity. The grenade is exclusive to Resistance: Fall of Man, and is only available on the game's second playthrough, first found in Manchester - "The Cathedral".
The Backlash Grenade does little actual damage. However, when thrown, the grenade creates a spherical barrier around itself. This barrier is impervious to most Chimeran weaponry, even the Auger Rifle, and will redirect any enemy shots back at the enemy who fired them. It will not block Angel spikes, Hedgehog Grenades or mines, Pulse Mines, the Arc Charger, or Roller acid spit. The grenade also damages any Chimera that walks into the shield, though most Chimera will avoid doing so. Waves of Leapers, Rollers or Menials will simply walk into the shield and kill themselves, though using such a scarce and powerful weapon against weak Chimera is a waste. If thrown at the player's feet, the grenade protects the player. It is also good as a countermeasure against Slipskulls and Steelheads, and very useful in dealing with the first wave of Advanced Hybrids when the player has no Bullseye Mark II.
Also, using a Backlash Grenade next to an explosive barrel will cause it to explode when the bullets travel around the shield, killing the player.