diff --git a/changelog.txt b/changelog.txt
index 210dc80..95506b0 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,3 +1,8 @@
+---------------------------------------------------------------------------------------------------
+Version: 3.3.4
+  Bugfixes:
+    - Fixed Rampant::on_entity_died
+
 ---------------------------------------------------------------------------------------------------
 Version: 3.3.3
   Bugfixes:
diff --git a/control.lua b/control.lua
index 9b7db63..924ec8f 100644
--- a/control.lua
+++ b/control.lua
@@ -491,7 +491,7 @@ local function onDeath(event)
                     end
                 end
 
-                if (getCombinedDeathGeneratorRating(chunk) < Universe.retreatThreshold) and cause and cause.valid then
+                if (getCombinedDeathGeneratorRating(chunk) < Universe.retreatThreshold) and cause and cause.valid and cause.get_health_ratio() ~= nil then
                     retreatUnits(chunk,
                                  cause,
                                  tick,
@@ -515,7 +515,7 @@ local function onDeath(event)
                     end
                 end
 
-                if cause and cause.valid then
+                if cause and cause.valid and cause.get_health_ratio() ~= nil then
                     retreatUnits(chunk,
                                  cause,
                                  tick,
diff --git a/info.json b/info.json
index bcab353..47a3cc1 100644
--- a/info.json
+++ b/info.json
@@ -1,7 +1,7 @@
 {
     "name" : "Rampant",
     "factorio_version" : "1.1",
-    "version" : "3.3.3",
+    "version" : "3.3.4",
     "title" : "Rampant",
     "author" : "Veden",
     "homepage" : "https://forums.factorio.com/viewtopic.php?f=94&t=31445",