diff --git a/code/controllers/configuration/entries/dynamic.dm b/code/controllers/configuration/entries/dynamic.dm
index 935164352e..98203b7d8a 100644
--- a/code/controllers/configuration/entries/dynamic.dm
+++ b/code/controllers/configuration/entries/dynamic.dm
@@ -94,6 +94,10 @@
 	config_entry_value = 10
 	min_val = 0
 
+/datum/config_entry/keyed_list/dynamic_mode_days
+	key_mode = KEY_MODE_TEXT
+	value_mode = VALUE_MODE_FLAG
+
 /datum/config_entry/keyed_list/storyteller_weight
 	key_mode = KEY_MODE_TEXT
 	value_mode = VALUE_MODE_NUM
diff --git a/code/modules/holiday/dynamic.dm b/code/modules/holiday/dynamic.dm
new file mode 100644
index 0000000000..fb50ea72ca
--- /dev/null
+++ b/code/modules/holiday/dynamic.dm
@@ -0,0 +1,10 @@
+/datum/holiday/dynamic
+	name = "Dynamic Day"
+
+/datum/holiday/dynamic/shouldCelebrate(dd, mm, yy, ww, ddd)
+	var/list/days = CONFIG_GET(keyed_list/dynamic_mode_days)
+	return ddd in days
+
+/datum/holiday/dynamic/celebrate()
+	GLOB.dynamic_forced_threat_level = rand(90, 100)
+	CONFIG_SET(string/force_gamemode, "dynamic") // prevents the round vote, which prevents extended
diff --git a/tgstation.dme b/tgstation.dme
index 0896e19bb9..0f88e36bc1 100644
--- a/tgstation.dme
+++ b/tgstation.dme
@@ -2263,6 +2263,7 @@
 #include "code\modules\food_and_drinks\recipes\tablecraft\recipes_spaghetti.dm"
 #include "code\modules\games\cas.dm"
 #include "code\modules\games\unum.dm"
+#include "code\modules\holiday\dynamic.dm"
 #include "code\modules\holiday\easter.dm"
 #include "code\modules\holiday\holidays.dm"
 #include "code\modules\holiday\halloween\bartholomew.dm"