i made a one command block creasion and its hard mode effect edision. i modified some mobs to be harder thoes are enderman,creeper,skeleton,zombie,whitch,spider and probably some other onec i dont remember and i made it a wile ago
if you want a new one i need 1 dia(thats it) the command is:



/summon FallingSand ~ ~1 ~ {Block:stone,Time:1,Passengers:[{id:FallingSand,Block:redstone_block,Time:1,Passengers:{id:FallingSand,Block:activator_rail,Time:1,Passengers:{id:MinecartCommandBlock,Command:gamerule commandBlockOutput false},{id:MinecartCommandBlock,Command:"/say hard mode effect edision"},{id:MinecartCommandBlock,Command:"/say tanks tp mrgarretto for making a awsome website how help me to make this"},{id:MinecartCommandBlock,Command:setblock ~10 ~-2 ~1 chain_command_block 4 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @etype=Witch,r=10] ~ ~ ~ /effect @p minecraft:nausea 10 255"}},{id:MinecartCommandBlock,Command:setblock ~11 ~-2 ~1 chain_command_block 4 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Enderman,r=5] ~ ~ ~ /tp @p ~ ~ ~ ~1 ~"}},{id:MinecartCommandBlock,Command:setblock ~12 ~-2 ~1 chain_command_block 4 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Zombie,r=2] ~ ~ ~ /effect @p minecraft:hunger 1 3"}},{id:MinecartCommandBlock,Command:setblock ~12 ~-2 ~ chain_command_block 3 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Skeleton,r=10] ~ ~ ~ /execute @p ~ ~ ~ /summon Arrow ~ ~3 ~ "}},{id:MinecartCommandBlock,Command:setblock ~11 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Villager,r=2] ~ ~ ~ /summon LightningBolt"}},{id:MinecartCommandBlock,Command:setblock ~10 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Spider,r=3] ~ ~ ~ /execute @p ~ ~ ~ /setblock ~ ~ ~ web 0 keep"}},{id:MinecartCommandBlock,Command:setblock ~9 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/effect @e[type=Creeper] minecraft:speed 1 5"}},{id:MinecartCommandBlock,Command:setblock ~8 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Enderman,r=5] ~ ~ ~ /tp @p ~ ~ ~1"}},{id:MinecartCommandBlock,Command:setblock ~7 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Enderman,r=5] ~ ~ ~ /tp @p ~-1 ~ ~ "}},{id:MinecartCommandBlock,Command:setblock ~6 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Enderman,r=5] ~ ~ ~ /tp @p ~ ~ ~-1"}},{id:MinecartCommandBlock,Command:setblock ~5 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Enderman,r=5] ~ ~ ~ /tp @p ~1 ~ ~ "}},{id:MinecartCommandBlock,Command:setblock ~4 ~-2 ~ chain_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Witch,r=10] ~ ~ ~ /effect @p minecraft:nausea 10 255"}},{id:MinecartCommandBlock,Command:setblock ~3 ~-2 ~ repeating_command_block 5 replace {auto:1,Command:"/execute @p ~ ~ ~ /execute @e[type=Blaze,r=10] ~ ~ ~ /execute @p ~ ~ ~ /setblock ~ ~ ~ fire 0 keep"}},{id:MinecartCommandBlock,Command:setblock ~ ~ ~1 command_block 0 replace {Command:fill ~ ~-3 ~-1 ~ ~ ~ air}},{id:MinecartCommandBlock,Command:setblock ~ ~-1 ~1 redstone_block},{id:MinecartCommandBlock,Command:kill @e[type=MinecartCommandBlock,r=1]}]}]}]}




have fun :)