diff --git a/Content.IntegrationTests/Tests/DoAfter/DoAfterServerTest.cs b/Content.IntegrationTests/Tests/DoAfter/DoAfterServerTest.cs
index 45c2759aa6..45c384f86c 100644
--- a/Content.IntegrationTests/Tests/DoAfter/DoAfterServerTest.cs
+++ b/Content.IntegrationTests/Tests/DoAfter/DoAfterServerTest.cs
@@ -21,6 +21,7 @@ namespace Content.IntegrationTests.Tests.DoAfter
   - type: DoAfter
 ";
 
+        [Serializable, NetSerializable]
         private sealed partial class TestDoAfterEvent : DoAfterEvent
         {
             public override DoAfterEvent Clone()