Vex

"We started talking about making more hostile mobs, so we started drawing a lot of doodles on paper and then I kind of liked just having a small humanoid shape with wings. It essentially looked like a little nasty angel or devil."

- Jeb about the Vex, July 17, 2017

Vexes are flying hostile mobs that are summoned in small groups by the spell-casting evoker.

Spawning
Vexes spawn naturally only as part of an evoker's summoning attack; the evoker signals this attack by producing off-white smoke and a high-pitched horn-like sound. Exactly 3 vexes will appear near the evoker. The evoker will summon vexes even if there are some still left alive from the last summoning.

Drops
The iron sword they hold normally has a 0% chance of dropping, because their main hand's  is. However, this chance increases by 1 percentage point per level of Looting. If dropped, the sword will be badly damaged.

Behavior


Vexes are hostile mobs that will naturally attack players, villagers or adult villagers (only if evokers summoned them), iron golems, wandering traders (only if evokers summoned them) and any other target as commanded by their summoning evoker. They are capable of flying through the air, and will pass through any block, including water, unharmed and uninhibited. When they are attacking, they glow red and lunge at their target. They are not affected by fire blocks or lava.

Vexes summoned by an evoker will start to take damage after 30 to 119 seconds, and will eventually die. This does not apply if the vex is summoned by a spawn egg or by the command.

When idle, vexes will wander within a 15×11×15 cuboid range centered on their evoker's position, unless summoned by a spawn egg or by the command.

Data values
Vexes have entity data associated with them that contains the various properties of the mob.