diff --git a/hub/CHANGELOG.md b/hub/CHANGELOG.md
index 98af6183..f42f45a1 100644
--- a/hub/CHANGELOG.md
+++ b/hub/CHANGELOG.md
@@ -1,3 +1,17 @@
+## v0.121.0 — `app_oom_storm`: a repeating OOM problem reaches the operator louder (2026-09-23, R-636)
+
+Controller v0.265.0 sends `app_oom_storm` (severity `error`) once per container run when the kernel's
+OOM-kill counter for the same run rises by 20+ within 30 minutes. `app_oom` (warning, once per run) is
+unchanged.
+
+- **Allow-listed AND operator-only, in the same commit** (`allowedEventTypes` + `operatorOnlyEvents`):
+  the details carry raw container names and memory figures, and a type allow-listed but not
+  operator-only would reach a household as raw English (the v0.78.0 defect). Pinned together by
+  `TestAppOOMStormIsAllowlistedAndOperatorOnly`.
+- **Per-app operator cooldown:** joined R-389's `perAppCooldownEvents` (the fence test widened on purpose,
+  with its reason) — two apps storming on one night are two alarms.
+- Red-proofs: three (REPORT).
+
 ## v0.120.0 — the household is TOLD when an update is undone or held (2026-09-23, `09` §3 decision 15)
 
 Controller v0.264.0 sends two new events when a guarded app update does not go through. This hub
diff --git a/hub/internal/api/chaosnight_events_test.go b/hub/internal/api/chaosnight_events_test.go
index 448cf145..03c91cf6 100644
--- a/hub/internal/api/chaosnight_events_test.go
+++ b/hub/internal/api/chaosnight_events_test.go
@@ -67,3 +67,16 @@ func TestAppUpdateOutcomesReachTheHousehold(t *testing.T) {
 		}
 	}
 }
+
+// R-636 (v0.121.0) — app_oom_storm is allow-listed AND operator-only, pinned together (allow-listed
+// but not operator-only is the v0.78.0 defect: raw English to a household).
+// RED-PROOF (REPORT.md): drop it from operatorOnlyEvents → "must be operator-only".
+func TestAppOOMStormIsAllowlistedAndOperatorOnly(t *testing.T) {
+	et := "app_oom_storm"
+	if !allowedEventTypes[et] {
+		t.Fatalf("%s must be in allowedEventTypes — the controller's push would 400", et)
+	}
+	if !notify.IsOperatorOnly(et) {
+		t.Fatalf("%s must be operator-only — container names and memory figures are not a household's business", et)
+	}
+}
diff --git a/hub/internal/api/handler.go b/hub/internal/api/handler.go
index a6441d38..e2e97de4 100644
--- a/hub/internal/api/handler.go
+++ b/hub/internal/api/handler.go
@@ -2140,6 +2140,9 @@ var allowedEventTypes = map[string]bool{
 	"pbsdr_adopted":       true,
 	"backup_tier_skipped": true,
 	"app_oom":             true,
+	// R-636 (hub v0.121.0, controller v0.265.0): the same container run OOM-killed 20+ times in 30 min.
+	// Operator-only (notify.operatorOnlyEvents) — registered in BOTH in the same commit.
+	"app_oom_storm": true,
 	// Special
 	"test": true,
 }
diff --git a/hub/internal/notify/dispatcher.go b/hub/internal/notify/dispatcher.go
index b3e737c5..1fca20e7 100644
--- a/hub/internal/notify/dispatcher.go
+++ b/hub/internal/notify/dispatcher.go
@@ -392,6 +392,9 @@ var perAppCooldownEvents = map[string]bool{
 	// v0.120.0: an update outcome is per app with no digest — two apps on one night are two alarms.
 	"app_update_undone": true,
 	"app_update_held":   true,
+	// v0.121.0 (R-636): a storm is one app's event with no digest behind it — two apps storming on one
+	// night are two alarms. (The controller already sends it at most once per container run.)
+	"app_oom_storm": true,
 }
 
 // perAppCustomerCooldownEvents is the CUSTOMER-leg sibling of perAppCooldownEvents (v0.120.0). The
@@ -652,6 +655,10 @@ var operatorOnlyEvents = map[string]bool{
 	// names — the household's side is the dashboard tag. Registered in the same commit.
 	"backup_tier_skipped": true,
 	"app_oom":             true,
+	// R-636 (v0.121.0, controller v0.265.0). The LOUDER sibling of app_oom: the same container run
+	// OOM-killed 20+ times in 30 minutes. Same audience, same reason — raw container names and memory
+	// figures; the household's side is the dashboard. Registered in the same commit that mints it.
+	"app_oom_storm": true,
 }
 
 // IsOperatorOnly reports whether an event type is barred from customer dispatch. Exported so the
diff --git a/hub/internal/notify/r389_cooldown_grain_test.go b/hub/internal/notify/r389_cooldown_grain_test.go
index 7886c403..ba55eb0d 100644
--- a/hub/internal/notify/r389_cooldown_grain_test.go
+++ b/hub/internal/notify/r389_cooldown_grain_test.go
@@ -68,7 +68,8 @@ func TestR389_StackSuffixIsAllowListedAndFailSoft(t *testing.T) {
 // an update outcome is one app's event, with no digest behind it — two apps undone on one night are
 // two alarms. The backup family stays coarse, as the fence says.
 func TestR389_TheAllowListHasExactlyOneMember(t *testing.T) {
-	want := []string{"app_start_failed", "app_update_held", "app_update_undone"}
+	// v0.121.0 widened it again, on purpose (R-636): an OOM storm is one app's event with no digest.
+	want := []string{"app_oom_storm", "app_start_failed", "app_update_held", "app_update_undone"}
 	ok := len(perAppCooldownEvents) == len(want)
 	for _, w := range want {
 		ok = ok && perAppCooldownEvents[w]
@@ -78,7 +79,7 @@ func TestR389_TheAllowListHasExactlyOneMember(t *testing.T) {
 		for k := range perAppCooldownEvents {
 			got = append(got, k)
 		}
-		t.Fatalf("perAppCooldownEvents = %v, want exactly [app_start_failed app_update_held app_update_undone]. Adding a member is the "+
+		t.Fatalf("perAppCooldownEvents = %v, want exactly [app_oom_storm app_start_failed app_update_held app_update_undone]. Adding a member is the "+
 			"fenced act: the backup family's cooldown is coarse ON PURPOSE (R-97a, R-182) so one full "+
 			"disk sends one digest, not one mail per app. Read the fence before widening this.", got)
 	}