Detecting an arrow in a mob?

Question

Currently, I have 3 bows that shoot arrows, and when each arrow strikes the ground (detects if in ground by inGround=1b tag), it will summon lightning, tnt, anvils, or whatever doohickey thing I'm able to think about.

This works pretty well, but sometimes, when I want to "target" a mob, I would have to shoot it at it's feet. And that's pretty annoying when sometimes, it will hit the mob, causing nothing to happen.

Is there a tag that detects if an arrow is in a mob? I remember there was a tag for detecting if an arrow is in a player (maybe player:1b?), but is there one for mobs?

If there isn't, is there a way to detect if an arrow is near a mob? That would be the closest thing I need for my project.

Thanks!

Answer 1

When the arrow is shot, summon an identical arrow with a marker riding it. Copy over the relevant nbt data, like motion. Now, you have replaced the original arrow with an arrow that has a marker riding it.

When the arrow hits the mob, the marker will be left over. You can use a predicate to check if your marker is no longer riding. Then, you can execute your commands with 100% certainty that it hit a target, and where.

---

A possible solution might look like this:

Repeating every tick:

#Replace arrow
execute as @e[type=arrow,tag=!new_arrow] at @s run summon arrow ~ ~ ~ {Tags:["new_arrow"],Passengers:[{id:"minecraft:marker",Tags:["arrow_rider"]}]}

execute as @e[type=arrow,tag=!new_arrow] at @s run data modify entity @e[type=arrow,tag=new_arrow,limit=1] Motion set from entity @s

kill @e[type=arrow,tag=!new_arrow]


#Event
execute as @e[type=marker,predicate=!<namespace>:is_riding_arrow] run summon lightning_bolt ~ ~ ~
execute as @e[type=marker,predicate=!<namespace>:is_riding_arrow] run playsound entity.wolf.hurt master @p

kill @e[type=marker,predicate=!<namespace>:is_riding_arrow]

Predicate file named is_riding_arrow.json located in <datapackname>/data/<namespace>/predicates/:

{
  "condition": "minecraft:entity_properties",
  "entity": "this",
  "predicate": {
    "nbt": "{Tags:[\"arrow_rider\"]}",
    "vehicle": {
      "type": "minecraft:arrow"
    }
  }
}

Answer 2

We are gonna:

• Detect an entity who was hurt and has tag
• Remove all tags
• Tag all entities who are nearby an arrow

Which are translated to:

execute as @e[tag=possible,nbt={HurtTime:10s}] run <your command>
tag @e remove possible
execute as @e[type=minecraft:arrow,nbt={inGround:0b}] at @s run tag @e[distance=..4] add possible

Note here, at the last command, we have @e[distance=..4]. The reason we use 4 (a big number) is that arrows travel too fast. If you lower that number, arrows shot at max speed may not trigger this.

The problem with having such a big number, is that any mob hurt while an arrow is flying by will activate it. This requires timing, but it is easy to do on purpose.