LZ fog before first drop and sentryguns to guard agains early FOB rush (they last only ten minits)

code/game/objects/structures/blocker.dm

@@ -61,6 +61,26 @@
 	attack_hand(M)
 	return XENO_NONCOMBAT_ACTION
 
+GLOBAL_LIST_INIT(landing_zone_fog, list())
+/obj/structure/blocker/landing_zone_fog
+	name = "dense fog"
+	desc = "It looks way too dangerous to traverse. Best wait until it has cleared up."
+	icon = 'icons/effects/effects.dmi'
+	icon_state = "smoke"
+	opacity = TRUE
+
+/obj/structure/blocker/landing_zone_fog/Initialize()
+	GLOB.landing_zone_fog += src
+	. = ..()
+
+/obj/structure/blocker/landing_zone_fog/proc/Clear()
+	GLOB.landing_zone_fog -= src
+	QDEL_IN(src, rand(3 SECONDS,5 SECONDS))
+
+/obj/structure/blocker/landing_zone_fog/Destroy()
+	GLOB.landing_zone_fog -= src
+	. = ..()
+
 
 /obj/structure/blocker/forcefield
 	name = "forcefield"
@@ -100,21 +120,16 @@
 
 	if(!visible)
 		invisibility = 101
-
-
 /obj/structure/blocker/forcefield/vehicles
 	types = list(/obj/vehicle/)
 
-
 /obj/structure/blocker/forcefield/vehicles/handle_vehicle_bump(obj/vehicle/multitile/multitile_vehicle)
 	if(multitile_vehicle.vehicle_flags & VEHICLE_BYPASS_BLOCKERS)
 		return TRUE
 	return FALSE
-
 /obj/structure/blocker/forcefield/multitile_vehicles
 	types = list(/obj/vehicle/multitile/)
 
-
 /obj/structure/blocker/forcefield/multitile_vehicles/handle_vehicle_bump(obj/vehicle/multitile/multitile_vehicle)
 	if(multitile_vehicle.vehicle_flags & VEHICLE_BYPASS_BLOCKERS)
 		return TRUE

code/modules/shuttle/shuttles/dropship.dm

@@ -261,6 +261,10 @@
 		xeno_announcement(SPAN_XENOANNOUNCE("The dropship has landed."), "everything")
 		xeno_announce = FALSE
 
+	for(var/fog in GLOB.landing_zone_fog)
+		var/obj/structure/blocker/landing_zone_fog/landing_zone_fog = fog
+		landing_zone_fog.Clear()
+
 /obj/docking_port/stationary/marine_dropship/on_dock_ignition(obj/docking_port/mobile/departing_shuttle)
 	. = ..()
 	turn_on_landing_lights()