Witch

Witches are dangerous hostile mobs that use splash potions as their ranged weapon. They also use beneficial potions on themselves defensively. Witches spawn in the Overworld at night, and in any area that has a light level of 7 or less. Each Witch Hut also spawns a Witch inside. Unlike Skeletons or Zombies, Witches do not burn up in sunlight.

Appearance
A Witch appears similar to a typical villager, but with paler skin, a smaller mouth, lavender eyes, a witch hat with a greenish buckle on the front, purple and green robes, brown leggings and grey feet. It has a large nose that moves gradually around its face, with a single small wart. While a Witch is drinking a potion, its nose will stick out. Witches periodically emit a purple particle effect similar to villagers' green effect.

Uses
When killed, witches can drop Glass Bottles, Glowstone Dust, Gunpowder, Redstone, Spider Eyes, Sticks, and Sugar. They drop 1–3 different item types, and 0-6 quantity of each, though with an overall maximum of six items total.

Witches also drop Potions of Healing, Fire Resistance, Swiftness and Water Breathing, but only when they die while drinking that potion.

Behavior
Witches use splash potions offensively, and drink ordinary potions defensively.

Offense

 * They will throw potions of slowness if the player is at least 8 blocks away and does not already have the Slowness status effect.
 * They will throw potions of poison if the player's health is at least and is not already poisoned.
 * They have a 25% chance of throwing potions of weakness if the player is within 3 blocks and does not already have the Weakness status effect.
 * If none of the above conditions are true, Witches default to using potions of harming.

These potions will affect other mobs in the effect range, not just the player.

Witches are also able to climb ladders, but only when forced to, as their AI does not handle ladders in a special way.

Defense

 * If set on fire, Witches drink a potion of fire resistance (though Witches don't catch fire in sunlight).
 * When damaged, even if only by, they will drink a potion of healing. Note that Witches can't attack while healing.
 * When a Witch's head is under water, it will drink a potion of water breathing.
 * When more than 11 blocks from a target, it will drink a speed potion to get closer and attack.

Witches are 85% resistant to splash potions of poison and instant damage.

Combat
A bow will likely be the best option, as their splash potions have only a short range (at most 12 blocks) as compared to arrows.

If a bow is not an option, a sprinting melee charge can work: When a witch sees a player from a distance (11-16 blocks away from her), she will try to drink a speed potion, giving the player time to sprint-jump in a straight line towards her. By the time the Witch finishes the potion, the player will be in jump-attack range. The witch will try to heal herself the first 4 to 5 seconds, but with any sword this should still be enough time to kill the Witch or force it to drink another healing potion before it has the opportunity to throw its offensive splash potions.

Keep a bucket of Milk handy to nullify potion (status) effects.

Trivia

 * A witch, like all mobs, can be geared using /summon.
 * If a witch shoots another witch with a potion, the witch who is hit will become angry and target the other witch, 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 other's splash potions.
 * Witches have more drops than any other mob in the game.
 * Witches have the most health of any normally aggressive mob other than boss mobs, Guardians, and Elder Guardians. They also have the fifth most health of any mob that spawns naturally in the Overworld, behind Endermen, Guardians, Elder Guardians, and Iron Golems.
 * Witches are one of the two naturally spawning mobs to regenerate health, the second being the Horse.
 * Witches do not utilize the equipment in their huts, but they can be used by players.
 * Unlike villagers, witches will despawn when the player is out of range, since they are hostile mobs.
 * The potion bottles that witches drink out of are purple, unlike the player's, which are white.
 * 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 the only hostile mob that don't make sounds.
 * Witches are extremely difficult to kill via suffocation or cacti (though not impossible), due to their frequent use of healing potions.
 * It's 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; both mobs spawn rarely, making this a more useful technique for attaining otherwise impossible to find villagers in resource-constrained maps, e.g. SkyBlock, nether-restricted servers, etc.
 * Witches are one of the five mobs that give debuffs to the player (the other four being the Wither, the Cave spider, the Wither skeleton, and the Elder Guardian).
 * They are also the only mob that can give more than one type of debuff.
 * All of the drops are used in potion brewing, except sticks. This makes for an exceptional potion ingredient farm.
 * In creative mode, a large number of witches can be spawned into a fenced area, then taunted into fighting by having a damaging potion thrown into their midst. Eventually all of the witches will fight each other because more of them are damaged each time another witch throws a potion.
 * If a game is started on peaceful then switched to a higher difficulty, all witch huts will be empty. This is because witches spawn with their huts at the beginning of the game.
 * If your view distance is greater than 8 then newly created terrain (including any witch huts and the witch that spawns with it) will be more than 128 blocks away, presumably causing the witch to immediately despawn.
 * Witches are one of four ranged mobs that spawn in the Overworld - the others being Guardians, Elder Guardians, and Skeletons.
 * When drinking a potion, a Witch's nose will point straight forward, instead of down.
 * Like Squid, Witches do not make any sounds, even when hit.