https://github.com/tgstation/tgstation/pull/66318

code/__DEFINES/mobfactions.dm

@@ -0,0 +1,4 @@
+/// If this seems rather...bare at the moment, its temporary. At the moment this will just hold the clown faction define
+/// Later all mob factions will be moved here and their current factions replaced with faction defines.
+
+#define FACTION_CLOWN "Clowns"

code/modules/jobs/job_types/clown.dm

@@ -99,6 +99,7 @@
 		M.mutadone_proof = TRUE
 	var/datum/atom_hud/fan = GLOB.huds[DATA_HUD_FAN]
 	fan.add_hud_to(H)
+	H.faction |= FACTION_CLOWN
 
 //Skyrat Edit Start: Floor Demon
 /datum/outfit/job/clown_free

code/modules/mob/living/simple_animal/hostile/retaliate/clown.dm

@@ -35,6 +35,7 @@
 	unsuitable_atmos_damage = 10
 	unsuitable_heat_damage = 15
 	footstep_type = FOOTSTEP_MOB_SHOE
+	faction = FACTION_CLOWN
 	var/attack_reagent
 
 /mob/living/simple_animal/hostile/retaliate/clown/Initialize(mapload)

tgstation.dme

@@ -112,6 +112,7 @@
 #include "code\__DEFINES\memory_defines.dm"
 #include "code\__DEFINES\mergers.dm"
 #include "code\__DEFINES\mob_spawn.dm"
+#include "code\__DEFINES\mobfactions.dm"
 #include "code\__DEFINES\mobs.dm"
 #include "code\__DEFINES\mod.dm"
 #include "code\__DEFINES\monkeys.dm"