Players have to wait 5 minutes between dying as a mouse and respawning as a mouse. Global variable mouse_respawn_time determines the respawn time in minutes.

Mice can no longer open airlocks.

Mice can no longer strip items from humans

Mice can no longer put other creatures into disposal units (though they can still climb into disposal units)

Message for when mice crawl into vents removed. Mouse nibbling message only displayed to observers half the time.

code/modules/mob/dead/observer/observer.dm

@@ -263,6 +263,10 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	set name = "Become mouse"
 	set category = "Ghost"
 
+	if(client.can_spawn_as_mouse == 0)
+		src << "<span class='warning'>You may only spawn again as a mouse more than [mouse_respawn_time] minutes after your death.</span>"
+		return
+
 	//find a viable mouse candidate
 	var/mob/living/simple_animal/mouse/host
 	var/obj/machinery/atmospherics/unary/vent_pump/vent_found

code/modules/mob/living/carbon/human/inventory.dm

@@ -461,6 +461,7 @@ It can still be worn/put on as normal.
 */
 /obj/effect/equip_e/human/done()	//TODO: And rewrite this :< ~Carn
 	target.cpr_time = 1
+	if(ismouse(source)) return //mice cannot strip people
 	if(!source || !target) return		//Target or source no longer exist
 	if(source.loc != s_loc) return		//source has moved
 	if(target.loc != t_loc) return		//target has moved

code/modules/mob/living/simple_animal/friendly/mouse.dm

@@ -84,9 +84,11 @@
 			if(loc==startloc)
 				var/obj/target_vent = vents[selection_position]
 				if(target_vent)
+					/*
 					for(var/mob/O in oviewers(src, null))
 						if ((O.client && !( O.blinded )))
 							O.show_message(text("<B>[src] scrambles into the ventillation ducts!</B>"), 1)
+					*/
 					loc = target_vent.loc
 			else
 				src << "\blue You need to remain still while entering a vent."
@@ -107,15 +109,19 @@
 	if (layer != TURF_LAYER+0.2)
 		layer = TURF_LAYER+0.2
 		src << text("\blue You are now hiding.")
+		/*
 		for(var/mob/O in oviewers(src, null))
 			if ((O.client && !( O.blinded )))
 				O << text("<B>[] scurries to the ground!</B>", src)
+		*/
 	else
 		layer = MOB_LAYER
 		src << text("\blue You have stopped hiding.")
+		/*
 		for(var/mob/O in oviewers(src, null))
 			if ((O.client && !( O.blinded )))
 				O << text("[] slowly peaks up from the ground...", src)
+		*/
 
 //make mice fit under tables etc? this was hacky, and not working
 /*
@@ -152,6 +158,17 @@
 			M << 'sound/effects/mousesqueek.ogg'
 	..()
 
+/mob/living/simple_animal/mouse/Die()
+	if(client)
+		client.mouse_respawn_timer()
+	..()
+
+/client/proc/mouse_respawn_timer()
+	can_spawn_as_mouse = 0
+	spawn(mouse_respawn_time * 600)
+		can_spawn_as_mouse = 1
+	return
+
 /*
  * Mouse types
  */