Witch

Witches are hostile, ranged mobs commonly spawning in Witch Huts. They're the second hostile ranged mob to spawn in the Overworld - the first being the skeleton.

Appearance
Witches have a similar appearance to the villager mob, and they wear purple and green robes with brown leggings underneath. They have large noses (which move slowly around on the Witch's face, as stated in Dinnerbone's tweet) with a single wart and have lavender colored eyes. Witches have smaller mouths than villagers. They wear a stereotypical witch hat with a green buckle on it, and their skin is slightly paler than that of a normal villager. However, witches periodically give off purple star particles similar to the villager's green stars.

Uses
When killed, witches can drop a great number of items, including Glass Bottles, Glowstone Dust, Gunpowder, Redstone, Spider Eyes, Sticks, and Sugar. They drop 1–3 item types, each 0–2 times. The same type can be chosen multiple times, therefore it is possible to get up to six of one item, or up to two of 3 different items.

Witches also rarely drop Potions of Healing, Fire Resistance and Swiftness, but only when they are killed while drinking that potion.

Combat
The witch mob uses splash potions of poison, weakness, harming, and slowness to fight the player. If the player is at least 8 blocks away and does not have the Slowness status effect, they will throw potions of slowness. If the player's health is at least and is not poisoned, they will throw potions of poison. If the player is within 3 blocks and does not have the Weakness status effect, they have a 25% chance of throwing potions of weakness. If none of these conditions are true, they default to using potions of harming. These potions will affect other mobs - not just the player. The witch does not burn in sunlight and when set on fire, drinks a potion of fire resistance. This can be seen when a bottle appears in the witch's hands. Utility mobs will attack witches as most other hostile mobs.

Witches are almost immune (85% damage resistance) to splash potions of poison and instant damage. When damaged, they will drink a potion of healing, healing themselves. When drinking a potion, a witch's nose will point straight forward (instead of down). While healing they can't attack the player. If lit on fire by lava or fire, witches will quickly drink potions of fire resistance, making lava and fire ineffective ways of killing witches.

A bow will likely be the best weapon for dealing with a witch, as the splash potions have only a short range (at most nine blocks) compared to arrows (which, when fired straight at full charge, travel 24 blocks). If a bow is not an option, a direct melee charge is the best option. Due to the witch's slow attack speed, if the player runs in a straight line and manages to get a quick sword strike in, the witch will try to heal themselves with a potion of healing, leaving the player to attack them without fear of retaliation.

Most effective way to kill a witch
The most effective way to kill witches is to hit it rapidly with an enchanted diamond sword. You can also shoot them rapidly with a bow from no less than 40 blocks away. Works with any enchanted bow, but doesn't work depending on your enviroment. (example: a tree blocking your shot)

Bugs

 * When a witch drinks a potion, the bottle will not show the drinking animation; only the witch itself.
 * Frequently, they will not spawn in the Witch Hut. However, sometimes they may spawn later after their hut generates.
 * Witch Huts are 2 blocks tall inside and witches are 3 blocks tall so their hats glitch through the ceiling.
 * In Superflat worlds witches don't spawn in witch huts after the world generates.

Trivia

 * If a witch shoots another witch with a potion, the witch who is hit will become angry, however it is impossible for either witch to kill the other (without help from a player) due to their use of healing potions and their resistance to each others' splash potions.
 * Though it's not actually a villager, the witch's skin is found in the Villager folder in minecraft.jar.
 * Witches have more mob drops than any other mob in the game.
 * Witches have the most health of any normally aggressive mob other than boss mobs. However, maximum-sized Magma Cubes may take more hits to kill due to their high armor value, and may also spawn numerous smaller versions whose collective health combined with that of their full-sized progenitor is well over that of one witch.
 * Witches are the only non-boss mob to naturally regenerate health.
 * Unlike villagers, witches rarely do respawn if a player is nearby the Witch Hut at night ( tested in version 1.5 )
 * Unlike villagers, witches do despawn when the player is out of range since they are hostile mobs.
 * Witch Huts are similar to the hut of Baba Yaga (a general name for witch in Slavic folklore) that stood on chicken legs.
 * The odds of a witch dropping the maximum amount of drops possible (6 items total) without a Looting enchantment are 1 in 81 (1.2%).
 * Witches are extremely difficult, though not impossible, to be killed by suffocation or drowning, due to their frequent use of healing potions.
 * If another naturally generating structure, such as a desert or jungle temple, spawns in close proximity with a swamp biome, there's a chance that multiple witches may also spawn inside them.
 * It would theoretically be possible to get a witch to hit a zombie villager with a splash potion of weakness, then cure the villager. This eliminates the need for gathering materials from the nether; however, the chances of finding a witch and a zombie villager in the same area would be very rare.