diff --git a/code/modules/mob/living/bot/ed209bot.dm b/code/modules/mob/living/bot/ed209bot.dm
index 9e50b4ddf71..570e58ec2ee 100644
--- a/code/modules/mob/living/bot/ed209bot.dm
+++ b/code/modules/mob/living/bot/ed209bot.dm
@@ -13,8 +13,8 @@
 
 	a_intent = I_HURT
 	mob_bump_flag = HEAVY
-	mob_swap_flags = ALLMOBS
-	mob_push_flags = ALLMOBS|HEAVY
+	mob_swap_flags = ~HEAVY
+	mob_push_flags = HEAVY
 
 	var/shot_delay = 4
 	var/last_shot = 0
diff --git a/code/modules/mob/living/carbon/human/human_defines.dm b/code/modules/mob/living/carbon/human/human_defines.dm
index 4546fab0507..7577fbb8f59 100644
--- a/code/modules/mob/living/carbon/human/human_defines.dm
+++ b/code/modules/mob/living/carbon/human/human_defines.dm
@@ -84,5 +84,5 @@
 	var/list/flavor_texts = list()
 
 	mob_bump_flag = HUMAN
-	mob_push_flags = ALLMOBS
-	mob_swap_flags = ALLMOBS
+	mob_push_flags = ~HEAVY
+	mob_swap_flags = ~HEAVY
diff --git a/code/modules/mob/living/carbon/human/species/species.dm b/code/modules/mob/living/carbon/human/species/species.dm
index 4b1b5bf2940..3ec44eca6d7 100644
--- a/code/modules/mob/living/carbon/human/species/species.dm
+++ b/code/modules/mob/living/carbon/human/species/species.dm
@@ -132,9 +132,9 @@
 		)
 
 	// Bump vars
-	var/bump_flag = HUMAN		// What are we considered to be when bumped?
-	var/push_flags = ALLMOBS	// What can we push?
-	var/swap_flags = ALLMOBS	// What can we swap place with?
+	var/bump_flag = HUMAN	// What are we considered to be when bumped?
+	var/push_flags = ~HEAVY	// What can we push?
+	var/swap_flags = ~HEAVY	// What can we swap place with?
 
 /datum/species/New()
 	if(hud_type)
diff --git a/code/modules/mob/living/carbon/human/species/xenomorphs/alien_species.dm b/code/modules/mob/living/carbon/human/species/xenomorphs/alien_species.dm
index b48593796f4..52410c5fc64 100644
--- a/code/modules/mob/living/carbon/human/species/xenomorphs/alien_species.dm
+++ b/code/modules/mob/living/carbon/human/species/xenomorphs/alien_species.dm
@@ -53,8 +53,8 @@
 		)
 
 	bump_flag = ALIEN
-	swap_flags = ALLMOBS
-	push_flags = ALLMOBS ^ ROBOT
+	swap_flags = ~HEAVY
+	push_flags = (~HEAVY) ^ ROBOT
 
 	var/alien_number = 0
 	var/caste_name = "creature" // Used to update alien name.
diff --git a/code/modules/mob/living/silicon/robot/robot.dm b/code/modules/mob/living/silicon/robot/robot.dm
index 592e6f3be54..7587eb9f449 100644
--- a/code/modules/mob/living/silicon/robot/robot.dm
+++ b/code/modules/mob/living/silicon/robot/robot.dm
@@ -10,7 +10,7 @@
 
 	mob_bump_flag = ROBOT
 	mob_swap_flags = ROBOT|MONKEY|SLIME|SIMPLE_ANIMAL
-	mob_push_flags = ALLMOBS //trundle trundle
+	mob_push_flags = ~HEAVY //trundle trundle
 
 	var/lights_on = 0 // Is our integrated light on?
 	var/used_power_this_tick = 0
diff --git a/code/setup.dm b/code/setup.dm
index a8eac57b7e6..07a53f51f1f 100644
--- a/code/setup.dm
+++ b/code/setup.dm
@@ -865,7 +865,7 @@ var/list/be_special_flags = list(
 #define SIMPLE_ANIMAL 32
 #define HEAVY 64
 
-#define ALLMOBS (HUMAN|MONKEY|ALIEN|ROBOT|SLIME|SIMPLE_ANIMAL)
+#define ALLMOBS (HUMAN|MONKEY|ALIEN|ROBOT|SLIME|SIMPLE_ANIMAL|HEAVY)
 
 #define NEXT_MOVE_DELAY 8