How to change Wither Skeleton skull drop rates (1.9)

Question

I'm aware that it is possible to change loot tables for mobs in Minecraft 1.9, making Ender Dragons drop an Elytra for example. This can be done either by creating a custom loot table or changing its entity data. For this example the command would be the following:

/entitydata @e[type=EnderDragon,tag=!hasTable] {ArmorDropChances:[0:1.1f,1:1.1f,2:1.1f,­3:1.1f],ArmorItems:[0:{},1:{},2:{id:elyt­ra,Count:1},3:{}],Tags:["hasTable"]}

Considering this, how would it be possible to make it so that Wither Skeletons always drop a skull?

Answer 1

I can't do it with loot tables, but I can still help you. Get a repeating command block and input:

/scoreboard objectives add test stat.killEntity.WitherSkeleton

Next, in the same direction as that command block is facing, place a chain command block and input this:

execute @p[score_test_min=1] ~ ~ ~ summon minecraft:wither_skull ~ ~ ~

which is good if your inventory is filling up fast, or

give @p[score_test_min=1] minecraft:skull 1 1

which is great if you're on a server and don't want people pinching your skulls. Next place another chain command block with:

/scoreboard players set @p[score_test_min=1] test 0

Note: Replace 'test' with the name of a scoreboard of your choosing, set the repeating command block to always active and unconditional, set the others to always active and conditional. This is multiplayer-friendly.

Bonus: If you use this for something more common (like cows and leather, for example), you might want to limit the availability by imposing a second requirement. To do this, put another repeating command block in place. Whichever repeating command block is closest to the chain command blocks can be a chain command block, but it must be set to conditional.

An example of a different kind of restriction is:

{SelectedItem:{id:minecraft:iron_axe,tag:{display:{Name:"Sacrificial Axe"}}}}

Best of luck!