Aftershock is an Inventionperk that deals extra damage in an area-of-effect damaging blast. Unprovoked monsters damaged by the perk will not retaliate.
Logging out or switching out your weapon with the perk will reset the stored damage to activate the effect. Switching to a weapon with Aftershock of any rank will prevent the damage stored from resetting.
Aftershock cannot hit the maximum percentage (40% per rank), as the damage range from Aftershock only goes in intervals of 0.4%. For example, a damage burst from Aftershock will deal 32% or 32.4% ability damage, but never in between.
In PvP, Aftershock is halved. A player would need to deal 25,000 damage for the effect to activate, and the damage is halved on average.
The damage stored from PvP is doubled, and you can switch game styles to activate Aftershock. For example, if you deal 40,000 damage in PvM and then 5,000 damage in PvP, or vice versa, Aftershock's effect will still activate.