Ever since the Creeper was added to Minecraft the popular (but overused) joke rose:
"Thatssssss a nice *whatever you created* you've got there, would be a ssssshame if ssssssomething happend to it"
A Creeper always looks the same. As all things in Minecraft are square shaped, it's head is square with a face. It's face has two empty eye sockets with an open frowning face, both leading into blackness. It's torso has no arms and it has four appendages which is what the Creeper uses to walk. It's entire body has multiple shades of green, which serves as a minor camouflage.
Early in minecraft, Notch (Minecraft's original programmer), made a mistake when modeling the pig mob. Instead of deleting the model and trying again, Notch kept the model and textured it to what it is now. Soon after the creeper's creation, it was once able to leave smoke in the explosion crater, but that was removed. In Indev, creepers exploded upon death only. Killing one would give the player around 200 points (but having points were later removed).
When a creeper is struck by lightning, it will gain a blue aura surrounding it. At this point, it becomes charged. The charged creeper has an explosion twice as powerful as TNT, and 50% more powerful than a regular creeper. When a charged creeper is hit by lightning, it will die, as lightning actually does damage to regular creepers, dispute the change. When a charged creeper is hit by lightning and dies, the occurrence is called "Overload"(or overkill................lol).
When killed, creepers drip gunpowder, used to craft TNT. When killed by a skeleton (whic is rare), a creeper can drop a music disk.
Having iron golems will be useless against creepers, because iron golems will not attack them. Snow golems however, WILL attack creepers, but snow golems cannot do any damage, and will only serve to knock them away or distract them. Ocelots can be tamed and made into cats. Creepers for some reason, fear cats, and will run away from them. Having floors made out of certain materials can work as an early warning system, although creepers are silent on most surfaces.