diff --git a/crates/horizon-client/src/game/commands.rs b/crates/horizon-client/src/game/commands.rs
index ea628917e..d33d19726 100644
--- a/crates/horizon-client/src/game/commands.rs
+++ b/crates/horizon-client/src/game/commands.rs
@@ -1851,7 +1851,7 @@ impl Game<'_> {
             if self.ui.difficulty == 0 && t.category == "monster" {
                 return Err(err("commands.summon.failed.peaceful", &[]));
             }
-            self.spawn_mob(&short, pos, true);
+            self.spawn_mob_spawned(&short, pos);
             name = Text::translate(&format!("entity.minecraft.{short}"), &[]);
         } else {
             match short.as_str() {
diff --git a/crates/horizon-client/src/game/creatures.rs b/crates/horizon-client/src/game/creatures.rs
index f7d4828f1..16b4cbc46 100644
--- a/crates/horizon-client/src/game/creatures.rs
+++ b/crates/horizon-client/src/game/creatures.rs
@@ -277,6 +277,19 @@ impl Game<'_> {
     pub(super) fn spawn_mob(&mut self, kind: &str, at: [f64; 3], persistent: bool) -> Option<u32> {
         self.spawn_mob_for(kind, at, persistent, false)
     }
+    /// `SummonCommand` and `SpawnEggItem`: vanilla spawns the mob, but it
+    /// never calls `Mob.setPersistenceRequired` for it, so the mob is not
+    /// persistent: the despawn rule holds it like any other mob, and only
+    /// its NBT can make it persistent.
+    pub(super) fn spawn_mob_spawned(&mut self, kind: &str, at: [f64; 3]) -> Option<u32> {
+        // The spawn is not a natural one (no jockeys, the patrol leader roll
+        // stays), but the mob is not persistent.
+        let id = self.spawn_mob_for(kind, at, true, false)?;
+        if let Some(m) = self.mobs.iter_mut().find(|m| m.id == id) {
+            m.persistent = false;
+        }
+        Some(id)
+    }
     /// `spawn_mob` for a patrol or raid (`EntitySpawnReason.PATROL` / `EVENT`),
     /// which never rolls a patrol leader.
     pub(super) fn spawn_mob_for(
@@ -334,7 +347,7 @@ impl Game<'_> {
             }
         };
         let id = self
-            .spawn_mob(kind, at, true)
+            .spawn_mob_spawned(kind, at)
             .ok_or_else(|| format!("unknown or unsupported mob {kind}"))?;
         if baby && let Some(m) = self.mobs.iter_mut().find(|m| m.id == id) {
             m.extra.age = if m.species() == Species::Sniffer {
@@ -4075,7 +4088,7 @@ impl Game<'_> {
         let (species, variant, color) =
             (parent.species(), parent.extra.variant, parent.extra.color);
         let target = self.mob_entity(&self.mobs[index]);
-        let Some(id) = self.spawn_mob(&kind, at, true) else {
+        let Some(id) = self.spawn_mob_spawned(&kind, at) else {
             return false;
         };
         if let Some(child) = self.mobs.iter_mut().find(|m| m.id == id) {
@@ -4121,7 +4134,7 @@ impl Game<'_> {
             f64::from(p[1]),
             f64::from(p[2]) + 0.5,
         ];
-        if self.spawn_mob(&kind, at, true).is_none() {
+        if self.spawn_mob_spawned(&kind, at).is_none() {
             return Ok(false);
         }
         self.swing_arm();
diff --git a/tools/command_exec_corpus.py b/tools/command_exec_corpus.py
index 9a86c44f7..fd527fc76 100644
--- a/tools/command_exec_corpus.py
+++ b/tools/command_exec_corpus.py
@@ -327,6 +327,11 @@ def entities():
         cmd('/data get entity @e[tag=attr,limit=1] Health'),
         cmd('/attribute @e[tag=attr,limit=1] minecraft:attack_damage base get'),
         cmd('/kill @e[tag=attr]'),
+        # A summoned mob is not persistent: vanilla never calls
+        # `Mob.setPersistenceRequired` for a mob it spawns (#2787).
+        cmd('/summon minecraft:zombie 4.5 210 12.5'),
+        cmd('/execute if entity @e[type=minecraft:zombie,nbt={PersistenceRequired:1b}]'),
+        cmd('/kill @e[type=minecraft:zombie]'),
         # An End crystal is an entity of its own: a type selector finds it,
         # reads it and kills it (#1531).
         cmd('/summon minecraft:end_crystal 4.5 210 8.5'),