Tutorials/Summoning jockeys

Summoning a jockey (a mob riding on top of another mob) can be useful for adventure maps and interesting to experiment with.

Natural Generation
The few naturally-spawning jockeys in the game include spider jockeys (skeleton riding a spider), chicken jockeys (a baby zombie riding a chicken), and also a skeleton trap (skeletons riding skeleton horses).

A spider jockey has a 1% chance of spawning out of every spider spawned, and in the Nether, there is an 80% chance of a spider jockey becoming a Wither skeleton jockey. Baby zombies have a 5% chance of spawning on a chicken and an additional 5% chance if there are no chickens in a 10x6x10 area. For a skeleton trap to spawn, there is a small fraction of a chance they will spawn under a lightning strike in a group of 4 (0.75–1.5% chance on Easy, 1.5–4% on Normal, and 2.8125–6.75% on Hard, depending on regional difficulty).

They can also each be summoned via commands:
 * Spider Jockey:


 * Chicken Jockey:


 * Skeleton Trap:

Passenger Behavior
The "passenger" or the mob on top, will always have control over the mob it is mounted on as of 1.12. This means no matter what the mount's intentions (attacking a villager, for example), the passenger will always have control over the mount. For example, if you have a skeleton on the bottom with a zombie on top, the Zombie will move the mount itself and pursue a villager instead of you (only if it notices the villager first, like all zombies). Mobs on the bottom have small resistance, they can move slowly towards their own intentions (attacking a player) but the second the passenger moves the mount will be forced to move to that location.



In a nutshell, the passenger will behave regularly if they are mounted on a mob, but they will have a speed boost (equivalent to the players walking speed, or the passengers speed if the Passenger's speed is faster than the players speed). For example, if you have a wolf mounted on a cow, and you punch the wolf, the wolf will ride the cow towards you and inflict damage, and it will also make nearby wolves (even wolf jockeys) hostile. If a skeleton mounts a mob, it can strafe (as skeletons do when attacking). The only exception are endermen. They will teleport away (with the passenger), if a projectile is shot through them. However, if the enderman is the passenger, it will not teleport away but it cannot be damaged by projectiles.

-If a passenger is teleported by the player it will dismount the passenger and leave the mount at the previous location. For example, if you teleport all skeletons to your location, it will take all the skeletons off the spiders and teleport them to your location.

-Passengers can be infinitely stacked as of 1.12, if you stack the Passengers tag correctly.

Mount Behavior
The mount, or the mob being ridden has little control since 1.12. (Before this update, the mount had complete control, the exception being chicken jockeys). They will have "resistance", however, where they will slowly (about 1/4th of their normal walking speed) try to do whatever they are intending (attacking a player, chasing a villager). However, the passenger will always have dominance over the mount and can move it at it's will. Mounts will always give the passenger a speed boost, equivalent of the player's walking speed, faster if the mount is naturally faster than the player (such as a hostile enderman).

However, if there are multiple mobs of the same genre this rule can cancel out. Let say you have 3 zombies stacked on top of each other and a cow on the very top. Well, if there are 5 zombies that's 5 x 0.25% of the speed, which means the zombies can go as fast as they want, but the cow still has dominance over movement and can easily move a different direction, but the second the cow stops moving the zombies will resume their intentions.

If the mount is a passive mob it cannot inflict its own damage, the passenger has to inflict its own damage. If you have a skeleton riding a cow the Skeleton can attack, not the cow. The only case is where the Mount is hostile, such as a spider, if can attack as well and leap (this is the only exception where a Mount can jump on its own), making it deadly for the player. A neutral mob, such as a polar bear can attack on its own if the polar bear itself is provoked.

It is always easier to defeat a jockey if you attack the mount before the passenger. Knockback will have no effect whatsoever on the passenger. However, setting the mount on fire will also set the passenger on fire. If a mount is a hostile mob (such as an skeleton), it can still shoot arrows at the player if the passenger is facing the player, as mount can turn on its own, but it takes a while due to its very small "resistance".

Making a vex a mount does not take away its ability to fly through solid blocks. This can be useful if you mount a zombie on a vex, making it have the ability to fly into houses and attack players or villagers (the zombie is still in control of the vex).

Always remember that no matter what, the passenger has complete control over movement of the mount. If you summon a cow riding a zombie the zombie can try to slowly move towards the player and attack him but the second the cow moves the Jockey will move wherever the cow desires with no resistance. The only exception to this rule would be flying mobs. Bats, ghasts and blazes cannot fly if they are passengers, but they can move the mount at higher speeds. If you place a ghast onto a spider, the ghast will strafe or move forwards (as it does when its attacking).

The only mobs that can move freely even with a passenger are the wither, The ender dragon, bats, squids, parrots, and horses. Passengers have no control over these mounts whatsoever (except horses - see below).

-If a mob is summoned onto a horse, that mob will have control over the horse until it bucks them off - just like a player. It will never be "tamed" by the mob, and will only stay on for a limited time.

-If a mount is teleported by the player, the passenger will stay on, even if it was not the specified mob. For example, if you teleport all spiders to your location, it will also teleport spiders with passengers (spider jockeys).

As of 1.12, skeletons summoned through 'passenger' or 'mount' will not have a bow. You have to either equip them with a weapon (or item) or summon a skeleton with one pre-equipped.



Examples


A flying skeleton, you can make the bat invisible with /effect.



A teleporting creeper.



A zombie wearing a diamond helmet riding a pig. The zombie can also control the pig's movement.



An overpowered skeleton jockey wearing full diamond armor, a bow, a shield, and with Strength, Speed, Jump Boost, and Fire Resistance effects.