Projectile impact effects, sounds and blood splatters. (#8444)

Based.

code/modules/organs/blood.dm

@@ -269,10 +269,14 @@ proc/blood_splatter(var/target, var/datum/reagent/blood/source, var/large, var/s
 	var/obj/effect/decal/cleanable/blood/B
 	var/decal_type = /obj/effect/decal/cleanable/blood/splatter
 	var/turf/T = get_turf(target)
+
 	if(istype(source,/mob/living/carbon/human))
 		var/mob/living/carbon/human/M = source
 		source = M.get_blood(M.vessel)
 
+	if(!istype(source))
+		source = null
+
 	// Are we dripping or splattering?
 	var/list/drips = list()
 	// Only a certain number of drips (or one large splatter) can be on a given turf.
@@ -284,6 +288,10 @@ proc/blood_splatter(var/target, var/datum/reagent/blood/source, var/large, var/s
 
 	// Find a blood decal or create a new one.
 	B = locate(decal_type) in T
+	if(T)
+		var/list/existing = filter_list(T.contents, decal_type)
+		if(length(existing) > 3)
+			B = pick(existing)
 	if(!B)
 		B = new decal_type(T)