Minecraft wiki entry for Experience_farming, associated text: Zombified Piglins have an additional quirk which is relevant here: Famously, if a player aggros one of them, the entire group aggros, and this furthermore spreads to any neutral ZPs who arrive on the scene. Less obviously, ''any'' death of an aggro'ed ZP counts as a player kill, so they will drop experience (and player-only drops of gold ingots and swords) even if killed by a crusher or other automatic method. A gold farm can accumulate nuggets passively while the player is distant, but if the player is willing to show up to aggro them, the farm can drop experience as well as extra gold (especially if the player wields a Looting weapon). The swords dropped may be enchanted (up to 25% chance), and these can also be disenchanted at a grindstone, before being smelted.