Minecraft wiki entry for Target, associated text: Targets emit a redstone signal when hit by most projectiles. This includes arrows, tridents, eggs, snowballs, splash potions, fire charges fired by a dispenser, firework rockets‌[Java Edition only][1], lingering potions, bottles o' enchanting‌[Java Edition only] [1], ender pearls‌[Java Edition only][1], and llama spit. The closer a projectile is to the center of the block, the stronger the redstone signal that is produced.