Creeper

The Creeper is a green, near-silent, ambush/kamikaze mob that was first introduced in Survival Test version 0.24(August 24, 2009). Upon getting close enough to the player, it will let out a loud hissing sound and detonate after 1.5 seconds. Rarely creepers do have an idle sound; it sounds similar to a dying creeper (not exploding/people often mistake this for a spider). They do not catch fire when in direct sunlight, unlike Zombies and Skeletons. There can be dangers of running into a creeper in full sunlight. This won't happen when you go to sleep in the beginning of night because creepers need darkness to spawn.

Creepers possess a reputation among players, mostly because they can destroy player-made shelters and structures. In addition, their dangerous nature and strange appearance has made them a widely-recognizable icon for Minecraft.

Behavior
Creepers make a foot stepping noise while walking on blocks like dirt and grass, but are otherwise silent unless they fall or are damaged.

A creeper that has been struck by lightning will have a blue aura around it, becoming a charged/electrified creeper. A charged creeper's explosion is twice as powerful as a normal one. They cannot be spawned naturally, though it is possible that a charged creeper can wander its way down from the surface into a deep labyrinth which the player is in and destroy them. This makes setting up walls/no passing zones with Soul Sand or death traps before unlit areas a more desired preemptive so the player can continue focusing on their projects with less to fear from charged creepers in caves than on the surface.

There is an oddity with a creeper if the player manages to block a creeper behind a Soul Sand one-way entrance. The player can approach up to two blocks without the creeper hissing, but if the player suddenly goes into sneak position, the creeper will hiss and initialize his count-down timer. This shows that creepers currently countdown farther away if the player is at a lower elevation, and will only countdown if much closer to the player while they are at a higher elevation. This is probably because players can outrun explosions at a higher altitude and be shielded from the blast thanks to the floor.

A creeper's detonation can be halted if the player moves out of its blast radius. It will stop hissing, and gradually reset its timer at the same rate that it counts down (for example, if it has been counting down for 1 second, it will take 1 second to "cool down"). A bug may also halt the creeper, without resetting the timer, by closing a door when its "counting down", this will make the creeper (if the door was closed as it inflated) to not return to its normal shape, or remain white, but this has only been seen in multiplayer. Killing a creeper before the countdown starts or finishes will not cause the creeper to detonate.

A creeper will still blow up with a wall one block thick between you, though the creeper must be able to see you to start the detonation process. This can often happen when homes are surrounded by short walls that creepers can jump high enough to look over. Creepers cannot see through glass, so if a glass wall or window one block thick exists between the a creeper and the player, the creeper's detonation sequence will not be triggered. Glass walls around entrances will reveal the creepers' nasty habit of hiding in ambush around corners; the disadvantage of this is that glass is not very durable should the creeper explode.

Strategy
Due to the stealthy nature of creepers, the player must remain vigilant at all times, especially when exploring caves and in forest biomes. Underground, creepers can spawn at any time, and at the surface, creepers will spawn at night or in dark shadowed locations (Light level 7 or less). When confronting a creeper, the safest way to fight one is from a distance, using a bow and a stock of arrows. It takes five arrows to kill a creeper, but it is perfectly reasonable to use arrows to weaken creepers in preparation for a finishing strike with a sword.

If you are going to fight a creeper with a sword, it is best to do so while standing in water. If you are not standing directly next to a creeper when it explodes, water's high blast resistance will dampen the explosion, and prevent you from taking damage.

Like all other mobs, creepers can be lit on fire.

For close combat, players can take advantage of the creeper's count-down cancellation by hitting the creeper, retreating and hitting it again until it is defeated. The player can also get close enough to a creeper from above to hit it with a melee weapon without the detonation sequence being activated. However, the player should keep in mind that creepers move fowards and counter-clockwise (left) when approaching a targeted player.

Alternatively, due to their straight-forward path finding, the player can dig three-block-deep pits to lure the creeper into and then strike from above. While two blocks may seem sufficient, there is a risk of having the creeper "boosted" up out of the pit when struck. This strategy has one major drawback in that it is quite possible the player will fall into their own pit while running backwards and become hoisted upon their own petard - the best idea in this situation is to place any block you like in the single space overhead, and wait until long past dawn.

Another alternative is to use a diamond sword and strike them twice, one right after the other. Mobs, like the player, have a 0.5 second buffer zone from being hit to being able to to be hit again. This is not recommended if there are multiple creepers in close proximity, though this works wonders in caves should a creeper suddenly fall down behind you. Remember, keys 1-9 correspond to using the item in that inventory slot so be ready to switch the moment you hear them hissing. If you are cornered with a diamond sword, this is the easiest way to deal with them. Run at them and keep tapping the attack button until they die. This technique also works with an Iron sword and Stone sword, though harder.

Creepers (as well as other mobs) can be attacked through the "windows" of both types of doors.

Explosion Properties
A creeper's explosion is 25% less powerful than that of TNT, with an explosive power of 3. As with TNT, all loose drops in the explosion radius will be destroyed - something to consider if the player is killed. Also like TNT, a certain percentage of blocks destroyed by the creeper will survive the blast and can be picked up. It is not unheard of for players to use this fact to get stone tools before bothering to make wooden ones by luring a creeper to open stone.

In terms of environmental damage, the harder the material caught in an explosion, the less damaging the explosion will be. Secure homes should be built with multiple layers of highly explosion-resistant materials.

Charged Creepers
Charged Creepers (aka Electrified Creepers, Electrocreepers, Supercharged Creepers or Thunder Creeps) are the latest monster that players need to be on the lookout for during lightning storms. They are distinguished from normal creepers by the blue glow surrounding them. A creeper will become charged if lightning strikes it, though this is an extremely rare occurrence due to the fact that lightning needs to strike within 3-4 blocks of the creeper to have any effect on it. The explosion from a charged creeper does more damage and has a greater range. Charged creeper explosions are 50% more powerful than TNT explosions. Also, craters left by charged creepers tend to be slightly more irregular in shape and consistency.

The player's shelter is only truly safe from charged creepers when using obsidian as a construction material. It is extremely hard to cancel a charged creeper's countdown due to the expanded blast radius, as it continues to count down so long as the player is range, just like a regular creeper.

Charged creepers do take damage from the lightning bolt, so it takes fewer attacks to kill them than an ordinary uninjured creeper.

As charged creepers are very rare, the easiest way to observe them is using 3rd party software such as mods.

Music Discs
If a creeper is killed by a skeleton's arrow, it will drop a Music Disc. How the creeper gets hurt before does not matter, as long as the final blow is made by a skeleton. The easiest way to achieve this is to hit a creeper with four arrows, and have a skeleton shoot it after. However, if the creeper is hit but not killed, and near the skeleton, it will attack the skeleton by exploding, and therefore will not drop a disc. Charged creepers will also drop music discs.

History
In Survival Test, the creeper's default look was a darker shade of green and flashed to a lighter green upon being hit. It behaved much like a zombie, except its attack dealt only two hearts worth of damage rather than the three of the zombie, or the more recent 8+. After taking some damage, it would flash, indicating that it was about to detonate. Upon being killed, it caused a 4x4x4 spherical explosion, leaving a small crater, destroying plenty of blocks and hurting any players if they were in the way. However, this did not destroy stone, so it was not possible to blow up the map. Before they saw the player their heads would "droop" down.

In survival test the creeper was worth 250 points when killed, this was later decreased to 200 points.

Drops
Survival Test:
 * No dropped items
 * 200 points

Alpha and Beta:
 * 0-2 units of Gunpowder
 * 1 Music Disc (when killed by a skeleton)

Creepers and Pop Culture
Creepers are probably Minecraft's most iconic mob. They are referenced in several of the items available at the Minecraft merch depot, and have evolved into a unique internet meme, with loads of fanart and "demotivational posters" made for it. The meme also includes a popular catchphrase: "That's[sssss] a very nice [something] you have there... It would be a [sssss]shame if anything happened to it..." referring to its tendency to sneak up on people and destroy it, and their characteristic "ssss" sound before explosion heralding impending disaster.

Trivia

 * Creepers are capable of climbing ladders despite lacking arms.
 * The creeper design is based on a failed attempt to make a pig model.
 * Notch has described creepers as "being crunchy, like dry leaves".
 * The Minecraft profile picture on Facebook is that of a Creeper's face.
 * Like all explosions, if a creeper detonates whilst surrounded/in water, its explosion has no effect on blocks, but will still cause damage to entities.
 * It is possible to detonate a creeper without taking damage.
 * Creepers were given a new taking damage sound after the Halloween Update.
 * Creepers swell up and grow in size before exploding.
 * Creepers are the only mob that a tame Wolf won't attack.
 * As of Beta 1.4, the 'A' in the Minecraft logo shows a Creeper's face.
 * If a creeper sees a player and were close enough to start their fuse, then before they defuse lose sight of that player, they will hold their fuse until they see that player again. In most cases they will hide behind a corner, and when they light their fuse they ALWAYS move to their right. Thus, they will stay behind that corner until the player comes close enough to be seen by the creeper again, and by then it is too late to get away. This occurs in both SSP and SMP. (Fixed as of 1.6)
 * There is a bug in SSP in which creepers sometimes use the sounds of other mobs, which can cause confusion in players.
 * As a creeper approaches a player, it tends to circle to their right (your left).
 * A creeper's fuse countdown is a little longer if it is in a web. It is not delayed by much, but usually enough for a player to get away if they are in danger of dying.
 * In rare occurrences a creeper won't explode if the player is in its sight range or if the player attacks it and will just disregard him/her.