Hostile Mob Farm?

[KiKi_Vanilla]

Lots of challenges involve mob drops but there are no good ways of getting them (apart from saving up lots of money to get zombie and skeleton spawners). But then how do you get spider drops and creeper drops?
I suggest having a Hostile Mob Farm as well as a Peaceful Mob Farm!

- KiKi_Vanilla & Dr_Milkshake
xoxo