Meltdown

 is a perk in Fallout: New Vegas.

Description
"Foes killed by your Energy Weapons emit a corona of harmful energy".

Effects
When a target has its hit points reduced to 0 by an energy weapon, this perk will create an explosion around the target, similar to a plasma grenade explosion, but smaller. A Meltdown explosion can cause critical hits and sneak attack criticals on nearby targets and propagate a chain reaction effect.