Shoot me if im wrong for wastin yo time, but I believe the only legit way to get a creeper spawner is from a mod or for 50k at the CS.
But if you're up for creeper killing, tpa to me at night <object class="emojione" data="
https://resources.enjin.com/1489581540/themes/core/images/emojione/svg/1f61b.svg?0" type="image/svg+xml" standby=":p">:p</object>
Ive got too many mobs round here. People make like 2 music discs in one minecraft-night :/