RUC = Repeating Unconditional Command Block
CUC = Chain Unconditional Command Block
CCC = Chain Conditional Command Block

Each set is a single row of connected command blocks

RUC > scoreboard objectives add block dummy
CUC > scoreboard players set @e[type=Enderman] block 1
CUC > entitydata @e[type=Enderman,score_block_min=1] {carried:minecraft:barrier}
CUC > execute @e[type=Enderman,score_block_min=1] ~ ~ ~ fill ~-2 ~-2 ~-2 ~2 ~2 ~2 air 0 replace barrier



RUC > scoreboard objectives add timer stat.timeSinceDeath
CUC > execute @a[score_timer_min=100] ~ ~ ~ fill ~-2 ~-2 ~-2 ~2 ~2 ~2 air 0 replace barrier
CCC > scoreboard players set @a[score_timer_min=100] timer 0



RUC > scoreboard objectives add BarrierClean dummy
CUC > scoreboard players set @e[type=Item] BarrierClean 1 {Item:{id:minecraft:barrier}}
CCC > kill @e[type=Item,score_BarrierClean=1,score_BarrierClean_min=1]