Creeper

The creeper is an infamous, green-camouflaged, near-silent kamikaze mob that will hide and ambush players before exploding. Creepers make an infrequent idle sound similar to a dying creeper, but softer (often mistaken for the spider noises). Unlike zombies and skeletons, creepers will not catch fire in direct sunlight and can wander around unharmed day and night. Underground or on the surface, creepers will spawn at night and in dimly lit locations with a light level of 7 or less.

Notch has described creepers as "being crunchy, like dry leaves".

Publicity
Creepers have a formidable reputation among players because of their potential to damage and destroy player-made structures, which has made them a widely-recognizable Minecraft icon. They are referenced in several of the items available at the Minecraft merchandise depot, and have become an internet meme complete with fanart, webcomic references, and demotivational posters. The meme has spawned the unofficial creeper's catchphrase (referring to its tendency to sneak up on players and hiss before it detonates).

"That'ssssss a very nice ___________ (everything, house, wolf, etc.) you have there... It would be a sssssshame if something happened to it..."

Uses
Creepers are the most easily obtainable source of gunpowder when killed (the more challenging alternatives being defeating ghasts and conquering dungeons), and are therefore critical to the production of TNT. Each creeper can drop 0 - 2 units of gunpowder upon death.

Music Discs
Creepers are the only mob that drops music discs, and can only do so if killed by a skeleton. How the creeper is damaged beforehand doesn't matter as long as the final blow is made by a skeleton's arrow. The easiest way to arrange this is to hit a creeper with 4 arrows or to strike it two times with an iron sword then lead it towards a skeleton to be shot at. Note that if a creeper is hit by a skeleton and not killed, it will run towards it and explode, which won't yield a music disc.

Charged creepers can also drop music discs.

Behavior
When within one block of a player, a creeper will hiss loudly and detonate after 1.5 seconds. Killing a creeper before the countdown starts or finishes will not cause the creeper to detonate. Creepers make audible footsteps while walking on dirt or grass, but are otherwise silent unless they fall or are otherwise damaged. If they see a player walking past them, they will turn to face them and start walking towards them in pursuit.

A creeper's detonation can be avoided if the player moves out of the blast radius (about 3 - 4 blocks). The hissing will stop as the creeper gradually reset its timer at the same rate that it counted down - if it has been counting down for 1 second, it will take 1 second to "cool down".

A creeper can still go off even if the player stands behind a one-block thick wall although the creeper must be able to see the player to actually detonate. This can often happen when homes are surrounded by fences or short walls that creepers can oversee when jumping. Creepers cannot "see" a player through glass, so if the creeper is behind a glass barrier one block thick, the player is safe. This should not be confused with the creeper's pursuit mode - like other aggressive mobs, once a creeper acquires a target, it can track it through solid blocks even if the player subsequently enters a completely enclosed building. Because creepers also do not burn in sunlight, it may be waiting for the player just around the door if he later emerges thinking it is safe.

If the player manages to block a creeper behind a soul sand one-way entrance, they can approach up to two blocks without triggering the countdown, but if they suddenly goes into a sneaking position, the creeper will hiss and initialize the countdown. This demonstrates that creepers countdown farther away if the player is at a lower elevation, and will only countdown if much closer to a player are at a higher elevation - probably because players can outrun explosions at a higher altitude and are more shielded from the blast there.

Explosive Properties
A creeper's explosion is 25% less powerful than that of TNT, with an explosive power of 3. Charged creeper explosions are 50% more powerful than TNT and twice that of a normal creeper's.

As with TNT and Ghast fireballs, all dropped items in the explosion radius will be destroyed. A certain percentage of blocks destroyed by the creeper will survive the blast and can be picked up. In terms of environmental damage, the harder the material caught in an explosion, the less damaging the explosion will be to anything behind the material.

Charged Creepers
A charged creeper is a type of creeper created when lightning strikes within 3 - 4 blocks of a normal creeper (a rare occurrence). Electrified creepers do not otherwise spawn naturally and can be distinguished from normal creepers by the blue glow surrounding them.

Charged creepers do take damage from the initial lightning strike, so it takes fewer attacks to kill them than an ordinary creeper. Their countdown timers act precisely the same, both range-wise and time-wise just like the ordinary version. However, the explosion caused by a charged creeper is much more powerful than an explosion caused by a regular creeper(as shown on the image above), and as such players will usually consider it their number one priority to kill, or distance themselves, from the electrified creeper.

Combat
The safest way to engage a creeper is from a distance. Using a bow, it takes 5 arrows to kill a creeper, but a reasonable alternative is to use 3 arrows to weaken it in preparation for a finishing iron sword strike, or 4 arrows if using a stone sword.

It is best to fight a creeper in close quarters while standing in water, as the water's high blast resistance will prevent environmental damage, though the player will still take damage. Additionally, creepers floating in water can be easily defeated using melee attacks while the player is underwater. Players can also take advantage of the creeper's countdown system by hitting it, retreating a few squares away, and repeating this until it dies. Alternatively, the player can find sufficiently high ground to strike a creeper from above with a melee weapon without the detonation sequence being activated. However, the player should keep in mind that creepers move forwards and to the right (your left) when in pursuit.

A diamond sword can quickly dispatch a creeper with two successive hits, one right after the other. This is not a recommended tactic around multiple creepers, though it can be a lifesaver when exploring underground should a creeper suddenly fall down behind the player in dim, tight areas.

If a creeper is below the player, the player can suffocate a creeper (and many other mobs) by placing a block of sand or gravel above the creeper as long as the block they are placing is on a wall or a block in front of the player and above the target mob. It will usually take one to two blocks to cover the creeper and when it is covered, the creeper will slowly suffocate to death. This is a slow way of eliminating a creeper but it will keep the player out of harm's way and preserve the durability of their weapon.

Defensive Measures
Due to creepers' natural stealth and potential hazards to the player and his/her structures, the player must remain vigilant at all times, especially in caverns and heavily wooded areas. Players are advised to keep a sword in their inventory to switch to at a moment's notice. To keep creeper populations down on the surface, a player can regularly sleep in a sheltered, well-lit bed at dusk since creepers spawn regularly if given the chance to do so at night.

Creepers' straightforward path finding tendencies can be used against them. The player can dig three-block-deep pits, lead the creeper towards them, and then hit it from above. While two blocks may seem sufficient to trap a creeper, there is a chance the creeper will be "boosted" up out of the pit when struck. This strategy has a couple of major drawbacks - for one, it can be difficult to use on multiple creepers, and it is possible for the player to fall into their own pit while running backwards. If hoist upon their own petard, the player is advised to block off the hole and wait until past dawn or tunnel away.

Construction Safeguards
Creepers and other mobs could be attacked through the windows of both iron and wooden doors as long as the doors were placed from the outside of the shelter before 1.6, however this is no longer possible. Glass walls around entrances can pre-empt the creepers' habit of hiding in ambush around corners (but this is offset by the disadvantage that glass is not very durable in an explosion). Ladders should be placed carefully, as creepers are capable of climbing ladders, despite lacking arms.

To minimize creeper damage to shelters and structures, the surrounding, interior, and roof areas should be well-lit. Buildings should be constructed out of sturdier materials like cobblestone or brick (with obsidian being the gold standard for blast resistant building blocks). Players should bear in mind that while an explosion will only destroy cobblestone construction to a depth of one block, it will destroy several blocks of dirt and may therefore expose a vulnerability to a building's unreinforced basement should it explode against a wall. Alternatively, the buildings can be built raised over the ground outside the reach of a creeper's blast radius or on a platform on the surface of a deep ocean or lake, where the surrounding water will absorb most of the explosive force from swimming creepers.

History
Creepers were first introduced in Survival Test version 0.24 on August 24, 2009. They were based on a failed pig model Notch had created.

In Survival Test, the creeper's default look was a darker shade of green and flashed to a lighter green upon being hit. Before creepers spotted the player their heads would droop down. Creepers behaved much like zombies except their attacks dealt only two hearts worth of damage rather than the zombies' three (or the more recent range of 8+). After taking damage, it would flash as an indicator of impending detonation. When killed, this creeper caused a 4 x 4 x 4 spherical explosion that left a sizable crater, destroyed plenty of blocks (with the exception of stone) and hurt any players nearby. The creeper was worth 250 points when killed, but this was later decreased to 200 points. As of Beta 1.4, the 'A' in the Minecraft logo included a creeper's face.

Trivia

 * 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.
 * Creepers are the only mob that a tame wolf won't attack.
 * It is possible to detonate a creeper without taking damage.
 * The Minecraft profile picture on Facebook is that of a creeper's face.
 * Creepers were given a new taking damage sound after the Halloween Update.
 * Creepers swell up and grow in size before exploding.
 * 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 (player's left). This behavior – which is also seen in skeletons – makes them slightly more challenging to kill than many other mobs, particularly if the player is using a sword or other melee distance tool rather than a bow.
 * A creeper's fuse countdown lasts a little longer if it encounters a cobweb, buying a little time for a player to flee if they are low on health.
 * In SMP, if a creeper is attacked by another player, and the other player runs out of sight, it will not attack any other players.