Head for a head.
Via Daily Mail:
ISIS fighters and an Afghan militia group have beheaded a total of eight men in a series of tit-for-tat revenge killings, according to an Afghan official.
Four men have been beheaded from each side, in a blood-thirsty decapitation war following a gunfight on Saturday.
The ISIS fighters were beheaded by the militia group, in pay-back after ISIS beheaded four of the militia members.
The killings have been going on in the eastern border province of Nangarhar, in Afghanistan.