Added organ mutations.

Only have sprites for humans yet.
Added is_usable() proc that checks for both limb missing or being a tentacle

code/modules/organs/organ.dm

@@ -11,6 +11,9 @@
 	proc/receive_chem(chemical as obj)
 		return 0
 
+/datum/organ/proc/get_icon()
+	return icon('icons/mob/human.dmi',"blank")
+
 //Handles chem traces
 /mob/living/carbon/human/proc/handle_trace_chems()
 	//New are added for reagents to random organs.

code/modules/organs/organ_external.dm

@@ -547,6 +547,11 @@
 		if(T)
 			T.robotize()
 
+/datum/organ/external/proc/mutate()
+	src.status |= ORGAN_MUTATED
+	owner << "<span class = 'notice'>Something is not right with your [display_name]...</span>"
+	owner.update_body()
+
 /datum/organ/external/proc/get_damage()	//returns total damage
 	return max(brute_dam + burn_dam - perma_injury, perma_injury)	//could use health?
 
@@ -556,6 +561,15 @@
 			return 1
 	return 0
 
+/datum/organ/external/get_icon()
+	if (status & ORGAN_MUTATED)
+		. = new /icon(owner.deform_icon, "[icon_name]")
+	else
+		. = new /icon(owner.race_icon, "[icon_name]")
+
+/datum/organ/external/proc/is_usable()
+	return !(status & (ORGAN_DESTROYED|ORGAN_MUTATED|ORGAN_DEAD))
+
 /****************************************************
 			   ORGAN DEFINES
 ****************************************************/
@@ -576,6 +590,14 @@
 	min_broken_damage = 70
 	body_part = LOWER_TORSO
 
+/datum/organ/external/groin/get_icon()
+	var/g = "m"
+	if(owner.gender == FEMALE)	g = "f"
+	if (status & ORGAN_MUTATED)
+		. = new /icon(owner.deform_icon, "[icon_name]_[g]")
+	else
+		. = new /icon(owner.race_icon, "[icon_name]_[g]")
+
 /datum/organ/external/l_arm
 	name = "l_arm"
 	display_name = "left arm"
@@ -653,27 +675,37 @@
 	body_part = HEAD
 	var/disfigured = 0
 
-	take_damage(brute, burn, sharp, used_weapon = null, list/forbidden_limbs = list())
-		..(brute, burn, sharp, used_weapon, forbidden_limbs)
-		if (!disfigured)
-			if (brute_dam > 40)
-				if (prob(50))
-					disfigure("brute")
-			if (burn_dam > 40)
-				disfigure("burn")
+/datum/organ/external/head/get_icon()
+	if (!owner)
+	 return ..()
+	var/g = "m"
+	if(owner.gender == FEMALE)	g = "f"
+	if (status & ORGAN_MUTATED)
+		. = new /icon(owner.deform_icon, "[icon_name]_[g]")
+	else
+		. = new /icon(owner.race_icon, "[icon_name]_[g]")
 
-	proc/disfigure(var/type = "brute")
-		if (disfigured)
-			return
-		if(type == "brute")
-			owner.visible_message("\red You hear a sickening cracking sound coming from \the [owner]'s face.",	\
-			"\red <b>Your face becomes unrecognizible mangled mess!</b>",	\
-			"\red You hear a sickening crack.")
-		else
-			owner.visible_message("\red [owner]'s face melts away, turning into mangled mess!",	\
-			"\red <b>Your face melts off!</b>",	\
-			"\red You hear a sickening sizzle.")
-		disfigured = 1
+/datum/organ/external/head/take_damage(brute, burn, sharp, used_weapon = null, list/forbidden_limbs = list())
+	..(brute, burn, sharp, used_weapon, forbidden_limbs)
+	if (!disfigured)
+		if (brute_dam > 40)
+			if (prob(50))
+				disfigure("brute")
+		if (burn_dam > 40)
+			disfigure("burn")
+
+/datum/organ/external/head/proc/disfigure(var/type = "brute")
+	if (disfigured)
+		return
+	if(type == "brute")
+		owner.visible_message("\red You hear a sickening cracking sound coming from \the [owner]'s face.",	\
+		"\red <b>Your face becomes unrecognizible mangled mess!</b>",	\
+		"\red You hear a sickening crack.")
+	else
+		owner.visible_message("\red [owner]'s face melts away, turning into mangled mess!",	\
+		"\red <b>Your face melts off!</b>",	\
+		"\red You hear a sickening sizzle.")
+	disfigured = 1
 
 /****************************************************
 			   EXTERNAL ORGAN ITEMS