diff --git a/modules/wave_defense/threat_events.lua b/modules/wave_defense/threat_events.lua
index 3d7b1c88..2e45cbaa 100644
--- a/modules/wave_defense/threat_events.lua
+++ b/modules/wave_defense/threat_events.lua
@@ -161,9 +161,10 @@ end
 local function on_entity_died(event)
 	local wave_defense_table = WD.get_table()
 	local entity = event.entity
-	if not entity.valid then	return end
+	if not entity.valid then return end
 	
 	if entity.type == "unit" then
+		if not threat_values[entity.name] then return end
 		wave_defense_table.threat = math.round(wave_defense_table.threat - threat_values[entity.name] * global.biter_health_boost, 2)
 		remove_unit(entity)
 		--acid_nova(entity)