diff --git a/src/acs/interface.cpp b/src/acs/interface.cpp
index cbd6533c1..864c1fa3f 100644
--- a/src/acs/interface.cpp
+++ b/src/acs/interface.cpp
@@ -249,6 +249,61 @@ void ACS_RunLapScript(mobj_t *mo, line_t *line)
 	map->scriptStartTypeForced(ACS_ST_LAP, scriptInfo);
 }
 
+/*--------------------------------------------------
+	void ACS_RunPositionScript(void)
+
+		See header file for description.
+--------------------------------------------------*/
+void ACS_RunPositionScript(void)
+{
+	Environment *env = &ACSEnv;
+
+	ACSVM::GlobalScope *const global = env->getGlobalScope(0);
+	ACSVM::HubScope *const hub = global->getHubScope(0);
+	ACSVM::MapScope *const map = hub->getMapScope(0);
+
+	map->scriptStartType(ACS_ST_POSITION, {});
+}
+
+/*--------------------------------------------------
+	void ACS_RunOvertimeScript(void)
+
+		See header file for description.
+--------------------------------------------------*/
+void ACS_RunOvertimeScript(void)
+{
+	Environment *env = &ACSEnv;
+
+	ACSVM::GlobalScope *const global = env->getGlobalScope(0);
+	ACSVM::HubScope *const hub = global->getHubScope(0);
+	ACSVM::MapScope *const map = hub->getMapScope(0);
+
+	map->scriptStartType(ACS_ST_OVERTIME, {});
+}
+
+/*--------------------------------------------------
+	void ACS_RunEmeraldScript(mobj_t *mo)
+
+		See header file for description.
+--------------------------------------------------*/
+void ACS_RunEmeraldScript(mobj_t *mo)
+{
+	Environment *env = &ACSEnv;
+
+	ACSVM::GlobalScope *const global = env->getGlobalScope(0);
+	ACSVM::HubScope *const hub = global->getHubScope(0);
+	ACSVM::MapScope *const map = hub->getMapScope(0);
+
+	ACSVM::MapScope::ScriptStartInfo scriptInfo;
+	ThreadInfo info;
+
+	P_SetTarget(&info.mo, mo);
+
+	scriptInfo.info = &info;
+
+	map->scriptStartTypeForced(ACS_ST_EMERALD, scriptInfo);
+}
+
 /*--------------------------------------------------
 	void ACS_Tick(void)
 
diff --git a/src/acs/interface.h b/src/acs/interface.h
index 18a3010f1..7c535ac3d 100644
--- a/src/acs/interface.h
+++ b/src/acs/interface.h
@@ -59,6 +59,17 @@ void ACS_Shutdown(void);
 void ACS_LoadLevelScripts(size_t mapID);
 
 
+/*--------------------------------------------------
+	void ACS_RunLevelStartScripts(void);
+
+		Runs the map's special scripts for opening
+		the level, and for all players to enter
+		the game.
+--------------------------------------------------*/
+
+void ACS_RunLevelStartScripts(void);
+
+
 /*--------------------------------------------------
 	void ACS_RunPlayerRespawnScript(player_t *player);
 
@@ -107,17 +118,6 @@ void ACS_RunPlayerDeathScript(player_t *player);
 void ACS_RunPlayerEnterScript(player_t *player);
 
 
-/*--------------------------------------------------
-	void ACS_RunLevelStartScripts(void);
-
-		Runs the map's special scripts for opening
-		the level, and for all players to enter
-		the game.
---------------------------------------------------*/
-
-void ACS_RunLevelStartScripts(void);
-
-
 /*--------------------------------------------------
 	void ACS_RunLapScript(mobj_t *mo, line_t *line);
 
@@ -135,6 +135,36 @@ void ACS_RunLevelStartScripts(void);
 void ACS_RunLapScript(mobj_t *mo, line_t *line);
 
 
+/*--------------------------------------------------
+	void ACS_RunPositionScript(void);
+
+		Runs the map's special script for when the level
+		goes past the POSITION period.
+--------------------------------------------------*/
+
+void ACS_RunPositionScript(void);
+
+
+/*--------------------------------------------------
+	void ACS_RunOvertimeScript(void);
+
+		Runs the map's special script for when the time
+		limit runs out and overtime begins.
+--------------------------------------------------*/
+
+void ACS_RunOvertimeScript(void);
+
+
+/*--------------------------------------------------
+	void ACS_RunEmeraldScript(mobj_t *mo);
+
+		Runs the map's special script for when the
+		Special Stage Chaos Emerald is collected.
+--------------------------------------------------*/
+
+void ACS_RunEmeraldScript(mobj_t *mo);
+
+
 /*--------------------------------------------------
 	void ACS_Tick(void);
 
diff --git a/src/acs/thread.hpp b/src/acs/thread.hpp
index 7e528608a..eff31eb29 100644
--- a/src/acs/thread.hpp
+++ b/src/acs/thread.hpp
@@ -48,6 +48,9 @@ enum acs_scriptType_e
 	ACS_ST_DEATH		=  3, // DEATH: Runs when a player dies.
 	ACS_ST_ENTER		=  4, // ENTER: Runs when a player enters the game; both on start of the level, and when un-spectating.
 	ACS_ST_LAP			=  5, // LAP: Runs when a player's lap increases from crossing the finish line.
+	ACS_ST_POSITION		=  6, // POSITION: Runs when the POSITION period ends.
+	ACS_ST_OVERTIME		=  7, // OVERTIME: Runs when Overtime starts in timed game modes.
+	ACS_ST_EMERALD		=  8, // EMERALD: Runs when the Chaos Emerald is collected in a Special Stage.
 };
 
 //
diff --git a/src/objects/ufo.c b/src/objects/ufo.c
index a4c46d58c..253b1a5e8 100644
--- a/src/objects/ufo.c
+++ b/src/objects/ufo.c
@@ -24,6 +24,7 @@
 #include "../k_waypoint.h"
 #include "../k_specialstage.h"
 #include "../r_skins.h"
+#include "../acs/interface.h"
 
 #define UFO_BASE_SPEED (42 * FRACUNIT) // UFO's slowest speed.
 #define UFO_SPEEDUP (FRACUNIT >> 1) // Acceleration
@@ -697,7 +698,7 @@ boolean Obj_SpecialUFODamage(mobj_t *ufo, mobj_t *inflictor, mobj_t *source, UIN
 		ufo->flags = (ufo->flags & ~MF_SHOOTABLE) | (MF_SPECIAL|MF_PICKUPFROMBELOW);
 		ufo->shadowscale = FRACUNIT/3;
 
-		P_LinedefExecute(LE_PINCHPHASE, ufo, NULL);
+		ACS_RunEmeraldScript(source);
 
 		S_StopSound(ufo);
 		S_StartSound(ufo, sfx_clawk2);
diff --git a/src/p_tick.c b/src/p_tick.c
index 22f9187be..4ed8fd83a 100644
--- a/src/p_tick.c
+++ b/src/p_tick.c
@@ -695,8 +695,20 @@ void P_Ticker(boolean run)
 	P_PrecipitationEffects();
 
 	if (run)
+	{
 		leveltime++;
 
+		if (starttime > introtime && leveltime == starttime)
+		{
+			ACS_RunPositionScript();
+		}
+
+		if (timelimitintics > 0 && leveltime == (timelimitintics + starttime + 1))
+		{
+			ACS_RunOvertimeScript();
+		}
+	}
+
 	timeinmap++;
 
 	if (G_GametypeHasTeams())