Creeper Crystals

Creeper Crystals is a small mod about harnessing creepers through Creeper Crystals (hence the name). To obtain Creeper Crystals, you must craft them. Combining an emerald with four gunpowder and four TNT will produce a few Creeper Crystal Shards. You can turn five of these shards into a full Creeper Crystal through crafting or combine a shard with gold and glowstone dust to make Holy Hand Grenades, a throwable item that causes a powerful explosion at the impact point without causing terrain damage. 

Creeper Crystals themselves can be used to make jukeboxes (in place of the diamond) or music discs. To make music discs, first craft a blank music disc with a creeper crystal, some iron nuggets, and some polished blackstone buttons. Then, combine the blank music disc with another item in the smithing table. A list of the items and resulting music discs are below. Pigstep cannot be crafted in this way, since it doesn't drop when a skeleton shoots a creeper.

Gunpowder => 11

Yellow dye => 13

Orange dye => Blocks

Lime dye => Cat

Red dye => Chirp

Slimeball => Far

Purple dye => Mall

Magenta dye => Mellohi

Black dye = Stal

White dye = Strad

Light blue dye = Wait

Green dye = Ward

Feel free to make suggestions for further additions to the mod in the comments!