diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 35f9931d72..e10a430d04 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -495,6 +495,7 @@ void AActor::Serialize(FSerializer &arc)
 		A("score", Score)
 		A("designatedteam", DesignatedTeam)
 		A("lastpush", lastpush)
+		A("activationtype", activationtype)
 		A("lastbump", lastbump)
 		A("painthreshold", PainThreshold)
 		A("damagefactor", DamageFactor)