diff --git a/code/datums/diseases/pierrot_throat.dm b/code/datums/diseases/pierrot_throat.dm
index 054e93868ba..89dd88ee35f 100644
--- a/code/datums/diseases/pierrot_throat.dm
+++ b/code/datums/diseases/pierrot_throat.dm
@@ -42,6 +42,9 @@
 	// Semi-permanent clown mask while in last stage of infection
 	if(locate(/obj/item/clothing/mask/gas/clown_hat) in H)
 		return
+	if(!istype(H)) // Xenos don't have masks. They can still feel silly though
+		return
+
 	if(!H.has_organ_for_slot(SLOT_HUD_WEAR_MASK) || !H.canUnEquip(H.get_item_by_slot(SLOT_HUD_WEAR_MASK)))
 		return
 
diff --git a/code/datums/diseases/wizarditis.dm b/code/datums/diseases/wizarditis.dm
index ab0d665b5a6..2bbb33bf4d4 100644
--- a/code/datums/diseases/wizarditis.dm
+++ b/code/datums/diseases/wizarditis.dm
@@ -58,6 +58,8 @@
 
 /datum/disease/wizarditis/proc/spawn_wizard_clothes()
 	var/mob/living/carbon/human/H = affected_mob
+	if(!istype(H))
+		return // Woe, wizard xeno upon ye
 
 	// Which slots can we replace?
 	var/list/eligible_slot_IDs = new