Decaying World - Only One Command by Insane_Creations

/summon MinecartCommandBlock ~ ~1 ~ {Command:kill @e[type=MinecartCommandBlock,r=1],Riding:{id:MinecartCommandBlock,Command:setblock ~ ~-1 ~1 redstone_block,Riding:{id:MinecartCommandBlock,Command:setblock ~ ~ ~1 command_block 0 replace {Command:fill ~ ~-3 ~-1 ~ ~ ~ air},Riding:{id:MinecartCommandBlock,Command:"/scoreboard players set @a Decay 0",Riding:{id:MinecartCommandBlock,Command:"/scoreboard objectives add Decay dummy",Riding:{id:MinecartCommandBlock,Command:"/gamerule commandBlockOutput false",Riding:{id:MinecartCommandBlock,Command:blockdata ~3 ~-2 ~-1 {Command:fill ~ ~ ~1 ~5 ~1 ~1 stone},Riding:{id:MinecartCommandBlock,Command:blockdata ~3 ~-2 ~1 {Command:fill ~ ~ ~-1 ~5 ~1 ~-1 redstone_block},Riding:{id:MinecartCommandBlock,Command:blockdata ~4 ~-2 ~-1 {Command:"/scoreboard players remove @a[score_Decay_min=1] Decay 1"},Riding:{id:MinecartCommandBlock,Command:blockdata ~4 ~-2 ~1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace grass"},Riding:{id:MinecartCommandBlock,Command:blockdata ~5 ~-2 ~-1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace stone"},Riding:{id:MinecartCommandBlock,Command:blockdata ~5 ~-2 ~1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace sand"},Riding:{id:MinecartCommandBlock,Command:blockdata ~6 ~-2 ~-1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace bedrock"},Riding:{id:MinecartCommandBlock,Command:blockdata ~6 ~-2 ~1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace sandstone"},Riding:{id:MinecartCommandBlock,Command:blockdata ~7 ~-2 ~-1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace mycelium"},Riding:{id:MinecartCommandBlock,Command:blockdata ~7 ~-2 ~1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace netherrack"},Riding:{id:MinecartCommandBlock,Command:blockdata ~8 ~-2 ~-1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace end_stone"},Riding:{id:MinecartCommandBlock,Command:blockdata ~8 ~-2 ~1 {Command:"/execute @a[score_Decay_min=0,score_Decay=0] ~ ~ ~ /fill ~7 ~7 ~7 ~-7 ~-7 ~-7 leaves 0 replace dirt"},Riding:{id:MinecartCommandBlock,Command:blockdata ~3 ~-1 ~-1 {Command:"/scoreboard players set @e[type=Item] Decay 1 {Item:{id:minecraft:blaze_powder}}"},Riding:{id:MinecartCommandBlock,Command:blockdata ~3 ~-1 ~1 {Command:"/execute @e[type=Item,score_Decay_min=1,score_Decay=1] ~ ~ ~ /tp @e[type=Item,r=1] ~ ~-1000 ~"},Riding:{id:MinecartCommandBlock,Command:blockdata ~4 ~-1 ~-1 {Command:"/execute @e[type=Item,score_Decay_min=1,score_Decay=1] ~ ~ ~ /scoreboard players set @a Decay 6000"},Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-2 ~ redstone_block,Riding:{id:MinecartCommandBlock,Command:fill ~3 ~-2 ~-1 ~4 ~-1 ~-1 command_block,Riding:{id:MinecartCommandBlock,Command:fill ~3 ~-2 ~-1 ~8 ~-2 ~-1 command_block,Riding:{id:MinecartCommandBlock,Command:fill ~3 ~-2 ~1 ~3 ~-1 ~1 command_block,Riding:{id:MinecartCommandBlock,Command:fill ~3 ~-2 ~1 ~8 ~-2 ~1 command_block,Riding:{id:MinecartCommandBlock,Command:setblock ~1 ~ ~ wall_sign 4 replace {Text1:"{text:\\\"Decaying World\\\",color:dark_green,bold:true}",Text2:"{text:\\\"Only One Command\\\",color:black}",Text3:"{text:\\\"by\\\",color:black}",Text4:"{text:\\\"Insane_Creations\\\",color:dark_blue}"},Riding:{id:MinecartCommandBlock,Command:setblock ~1 ~-1 ~ wall_sign 4 replace {Text1:"{text:\\\"Destroy\\\",color:dark_red,bold:true}",Text2:"{text:\\\"Machine\\\",color:dark_red,bold:true}",Text4:"{text:\\\"\\\",clickEvent:{action:\\\"run_command\\\",value:\\\"fill ~ ~-2 ~-2 ~9 ~3 ~2 air\\\"}}"},Riding:{id:MinecartCommandBlock,Command:fill ~2 ~-2 ~-2 ~9 ~-1 ~2 stained_glass 3 replace stained_hardened_clay 3,Riding:{id:MinecartCommandBlock,Command:fill ~2 ~-3 ~-2 ~9 ~ ~2 stained_hardened_clay 3 hollow,Riding:{id:MinecartCommandBlock,Command:gamerule commandBlockOutput false,Riding:{id:MinecartCommandBlock,Riding:{id:FallingSand,Block:activator_rail,Time:1,Riding:{id:FallingSand,Block:redstone_block,Time:1,Riding:{id:FallingSand,Block:stone,Time:1}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}