Minecraft – Summon an item frame with custom item which have data on it

I solved this question a while ago, and I lost my save file somewhere, so I'm not sure how exactly I did this, but here's basically what I did:

• Make a wall of command blocks behind any plain colored block behind a wall of trapdoors
• Program the command blocks to spawn a leather armor item on the trapdoor 2 blocks away
• Rearrange command blocks to change colors

• To refresh the screen, kill all the items on the trapdoors and power all the command blocks

  CX_   C=Command
  CX_   X=Any block
  CX_   _=Trapdoor
  

RootVehicle is a player-only tag. You cannot directly detect if a non-player entity is riding something.

You would need to rely on the host, which makes multi-target situations unreliable (such that you can only reliably have 1 set of those mobs at a time for it to work perfectly).

For example, you would mark the skeleton for death but cause the horse to remove that label. If the horse dies, it no longer exists to remove the label and the skeleton would die.

/scoreboard players tag @e[type=Skeleton,name=pony] add kill
/execute @e[type=EntityHorse,tag=pony] ~ ~ ~ /scoreboard players tag @e[type=Skeleton,name=pony] remove kill

/kill @e[type=Skeleton,name=pony,tag=kill]