diff --git a/app/Listeners/CreateActivity.php b/app/Listeners/CreateActivity.php
index 736aea1..bc59e76 100644
--- a/app/Listeners/CreateActivity.php
+++ b/app/Listeners/CreateActivity.php
@@ -34,7 +34,7 @@ public function handle(EventCreated $eventCreated): void
         $event = $eventCreated->getEvent();
 
         $adjacentActivity = $this->getAdjacentActivity($event);
-        if ($adjacentActivity && $this->canBeMergedWithAdjacentActivity($adjacentActivity, $event)) {
+        if ($adjacentActivity && $this->canAbsorbEvent($adjacentActivity, $event)) {
             $startedAt = $adjacentActivity->started_at;
             if ($event->started_at) {
                 $startedAt = $adjacentActivity->started_at->min($event->started_at);
@@ -49,7 +49,7 @@ public function handle(EventCreated $eventCreated): void
         }
     }
 
-    private function canBeMergedWithAdjacentActivity(Activity $lastActivity, Event $event): bool
+    private function canAbsorbEvent(Activity $lastActivity, Event $event): bool
     {
         $suggestion = $lastActivity->entrySuggestion;
 
@@ -98,21 +98,52 @@ private function createActivityFromEvent(Event $event): ?Activity
         $activity->is_internal = $event->is_internal;
         $activity->event_type_id = $event->eventType->id ?? null;
 
+        $absorbedActivities = collect();
         if (config('timatic.feature.activity_overlap_detection')) {
-            $activity = $this->handleOverlappingActivities($activity);
+            $absorbedActivities = $this->trimOverlappingActivities($activity);
+
+            if (! $activity->ended_at->isAfter($activity->started_at)) {
+                $this->attachEventToCoveringActivity($event);
+
+                return null;
+            }
         }
 
-        if ($activity) {
-            $this->db->transaction(function () use ($activity, $event) {
-                $activity->save();
-                $activity->events()->save($event);
+        $this->db->transaction(function () use ($activity, $event, $absorbedActivities) {
+            $activity->save();
+            $activity->events()->save($event);
+
+            $absorbedActivities->each(function (Activity $absorbedActivity) use ($activity) {
+                $absorbedActivity->events()->update(['activity_id' => $activity->id]);
+                $absorbedActivity->delete();
             });
-        }
+        });
 
         return $activity;
     }
 
-    private function handleOverlappingActivities(Activity $activity): ?Activity
+    private function attachEventToCoveringActivity(Event $event): void
+    {
+        /** @var ?Activity $coveringActivity */
+        $coveringActivity = Activity::query()
+            ->where('user_id', $event->user_id)
+            ->where('started_at', '<=', $event->ended_at)
+            ->where('ended_at', '>=', $event->ended_at)
+            ->first();
+
+        if ($coveringActivity && $this->canAbsorbEvent($coveringActivity, $event)) {
+            $coveringActivity->events()->save($event);
+        }
+    }
+
+    /**
+     * Trims activities overlapping the new activity's period. An existing activity whose
+     * trimmed period would collapse is returned for absorption: the new activity takes
+     * over its events and the empty activity is deleted.
+     *
+     * @return Collection<int, Activity>
+     */
+    private function trimOverlappingActivities(Activity $activity): Collection
     {
         /** @var Collection|Activity[] $overlappingActivities */
         $overlappingActivities = Activity::query()
@@ -137,7 +168,9 @@ private function handleOverlappingActivities(Activity $activity): ?Activity
             })
             ->get();
 
-        $overlappingActivities->each(function ($overlappingActivity) use ($activity) {
+        $absorbedActivities = collect();
+
+        $overlappingActivities->each(function ($overlappingActivity) use ($activity, $absorbedActivities) {
             /** @var Activity $overlappingActivity */
             if (! is_null($overlappingActivity->eventType)
                 && $overlappingActivity->eventType->weight >= (int) $activity->eventType?->weight) {
@@ -150,14 +183,15 @@ private function handleOverlappingActivities(Activity $activity): ?Activity
                 } else {
                     $overlappingActivity->started_at = $activity->ended_at;
                 }
-                $overlappingActivity->save();
+
+                if ($overlappingActivity->ended_at->isAfter($overlappingActivity->started_at)) {
+                    $overlappingActivity->save();
+                } else {
+                    $absorbedActivities->push($overlappingActivity);
+                }
             }
         });
 
-        if ($activity->ended_at->isAfter($activity->started_at)) {
-            return $activity;
-        } else {
-            return null;
-        }
+        return $absorbedActivities;
     }
 }
diff --git a/app/Models/Activity.php b/app/Models/Activity.php
index 9c64d85..2b4f717 100644
--- a/app/Models/Activity.php
+++ b/app/Models/Activity.php
@@ -10,7 +10,6 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
-use Illuminate\Database\Eloquent\Relations\HasOne;
 use Illuminate\Support\Collection;
 
 /**
@@ -85,10 +84,10 @@ public function entrySuggestion(): BelongsTo
     }
 
     /**
-     * @return HasOne<EventType, $this>
+     * @return BelongsTo<EventType, $this>
      */
-    public function eventType(): HasOne
+    public function eventType(): BelongsTo
     {
-        return $this->hasOne(EventType::class);
+        return $this->belongsTo(EventType::class);
     }
 }
diff --git a/tests/Integration/Activity/CreateActivityTest.php b/tests/Integration/Activity/CreateActivityTest.php
index b563783..aca97cd 100644
--- a/tests/Integration/Activity/CreateActivityTest.php
+++ b/tests/Integration/Activity/CreateActivityTest.php
@@ -270,3 +270,115 @@
 
     expect(Activity::query()->count())->toEqual(2);
 });
+
+test('a fully covered lower-weight activity is absorbed instead of getting a negative duration', function () {
+    config()->set('timatic.feature.activity_overlap_detection', true);
+    Illuminate\Support\Facades\Event::fake();
+
+    $eventTypeLight = EventType::factory()->state(['weight' => 1])->create();
+    $eventTypeHeavy = EventType::factory()->state(['weight' => 999])->create();
+    $user = User::factory()->create();
+
+    /** @var Event $coveredEvent */
+    $coveredEvent = Event::factory()->create([
+        'user_id' => $user->id,
+        'event_type_id' => $eventTypeLight->id,
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 5, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 10, second: 0),
+    ]);
+
+    /** @var CreateActivity $listener */
+    $listener = app(CreateActivity::class);
+    $listener->handle(new EventCreated($coveredEvent));
+
+    /** @var Event $coveringEvent */
+    $coveringEvent = Event::factory()->create([
+        'user_id' => $user->id,
+        'event_type_id' => $eventTypeHeavy->id,
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 0, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 15, second: 0),
+    ]);
+    $listener->handle(new EventCreated($coveringEvent));
+
+    expect(Activity::count())->toBe(1)
+        ->and(Activity::whereColumn('started_at', '>=', 'ended_at')->count())->toBe(0)
+        ->and($coveredEvent->fresh()->activity_id)->toBe($coveringEvent->fresh()->activity_id);
+});
+
+test('an event fully covered by a matching activity attaches to that activity', function () {
+    config()->set('timatic.feature.activity_overlap_detection', true);
+    Illuminate\Support\Facades\Event::fake();
+
+    $sameState = [
+        'event_type_id' => EventType::factory()->state(['weight' => 1])->create()->id,
+        'customer_id' => 'customerX',
+        'ticket_number' => 'TIC-1',
+        'user_id' => User::factory()->create()->id,
+    ];
+
+    /** @var Event $coveringEvent */
+    $coveringEvent = Event::factory()->create(array_merge($sameState, [
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 0, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 30, second: 0),
+    ]));
+
+    /** @var CreateActivity $listener */
+    $listener = app(CreateActivity::class);
+    $listener->handle(new EventCreated($coveringEvent));
+
+    /** @var Event $coveredEvent */
+    $coveredEvent = Event::factory()->create(array_merge($sameState, [
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 5, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 10, second: 0),
+    ]));
+    $listener->handle(new EventCreated($coveredEvent));
+
+    expect(Activity::count())->toBe(1)
+        ->and($coveredEvent->fresh()->activity_id)->toBe($coveringEvent->fresh()->activity_id);
+});
+
+test('a covered event of another customer stays unattached instead of mixing customers', function () {
+    config()->set('timatic.feature.activity_overlap_detection', true);
+    Illuminate\Support\Facades\Event::fake();
+
+    $eventTypeId = EventType::factory()->state(['weight' => 1])->create()->id;
+    $user = User::factory()->create();
+
+    /** @var Event $coveringEvent */
+    $coveringEvent = Event::factory()->create([
+        'event_type_id' => $eventTypeId,
+        'customer_id' => 'customerX',
+        'ticket_number' => 'TIC-1',
+        'user_id' => $user->id,
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 0, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 30, second: 0),
+    ]);
+
+    /** @var CreateActivity $listener */
+    $listener = app(CreateActivity::class);
+    $listener->handle(new EventCreated($coveringEvent));
+
+    /** @var Event $coveredEvent */
+    $coveredEvent = Event::factory()->create([
+        'event_type_id' => $eventTypeId,
+        'customer_id' => 'customerY',
+        'ticket_number' => 'TIC-2',
+        'user_id' => $user->id,
+        'started_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 5, second: 0),
+        'ended_at' => Carbon::now()->subWeek()->setTime(hour: 10, minute: 10, second: 0),
+    ]);
+    $listener->handle(new EventCreated($coveredEvent));
+
+    expect(Activity::count())->toBe(1)
+        ->and($coveredEvent->fresh()->activity_id)->toBeNull();
+});
+
+it('loads the event type of an activity', function () {
+    Illuminate\Support\Facades\Event::fake();
+    $eventType = EventType::firstOrCreate(['id' => 'ticket_saved'], ['weight' => 1]);
+
+    $activity = Activity::factory()->create(['event_type_id' => $eventType->id]);
+
+    expect($activity->eventType)->toBeInstanceOf(EventType::class)
+        ->and($activity->eventType->id)->toBe('ticket_saved');
+});