Each charged creeper drops something!
First of all, a charged creeper will spawn at night if you summon the spawner! Here is its' drops:
TNT, Exploder (TNT Minecart) Water, Obsidian, Gray Sugar (100%), Gunpowder, Arrow of Slowness (34%), Elytra (1%) - The elytra is what makes this charged creeper awesome! But be aware,don't AFK in the grinder you made if you're going to attack it or it will explode; oh yeah, you have to stay 15 seconds by it for it to explode a huge amount of blocks! :O I recommend you to attack this guy with a bow to not only not scare you... but to let you attack the creepers in that grinder/spawner. Good Luck! :)