Creepers are common hostile mobs that explode when close to the player. They naturally spawn in the Overworld on top of solid blocks with a light level of 7 or less

What it Drops

Creepers drop 0-2 gunpowder, and a music disc if killed by a skeleton arrow. They also drop a creeper head if killed by a charged creeper's explosion. They drop 5 experience when killed by a player or tamed wolf.

Charged Creepers

A charged creeper is created only when lightning strikes within 3–4 blocks of a normal creeper, which significantly increases its explosive power. Charged creepers are distinguished from normal creepers by the blue aura surrounding them.Their countdown timers are the same as normal creepers, both in terms of range and time. With a power of 6, an explosion caused by a charged creeper is twice as powerful as the explosion caused by a regular creeper. Their explosions will cause a zombie, skeleton, wither skeleton, or other creeper to drop the corresponding mob head, one per explosion.

Here's where I got my information:)