The grab item won't be created and instantly deleted on their New() when you click a mob anchored.

code/modules/mob/living/carbon/alien/humanoid/humanoid.dm

@@ -261,7 +261,7 @@
 			help_shake_act(M)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src)
 

code/modules/mob/living/carbon/alien/larva/larva.dm

@@ -233,7 +233,7 @@
 			help_shake_act(M)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
 

code/modules/mob/living/carbon/human/human_attackalien.dm

@@ -7,7 +7,8 @@
 		if ("help")
 			visible_message(text("\blue [M] caresses [src] with its scythe like arm."))
 		if ("grab")
-			if(M == src)	return
+			if(M == src || anchored)
+				return
 			if (w_uniform)
 				w_uniform.add_fingerprint(M)
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src)

code/modules/mob/living/carbon/human/human_attackhand.dm

@@ -33,7 +33,7 @@
 					src << "<span class='unconscious'>You feel a breath of fresh air enter your lungs. It feels good.</span>"
 
 		if("grab")
-			if(M == src)
+			if(M == src || anchored)
 				return 0
 			if(w_uniform)
 				w_uniform.add_fingerprint(M)

code/modules/mob/living/carbon/metroid/metroid.dm

@@ -432,7 +432,7 @@
 			help_shake_act(M)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
 
@@ -523,7 +523,7 @@
 						O.show_message(text("\red <B>[] has attempted to lunge at [name]!</B>", M), 1)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
 

code/modules/mob/living/carbon/monkey/monkey.dm

@@ -160,7 +160,7 @@
 						O.show_message(text("\red <B>[] has attempted to punch [name]!</B>", M), 1)
 		else
 			if (M.a_intent == "grab")
-				if (M == src)
+				if (M == src || anchored)
 					return
 
 				var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
@@ -230,7 +230,7 @@
 						O.show_message(text("\red <B>[] has attempted to lunge at [name]!</B>", M), 1)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
 

code/modules/mob/living/silicon/robot/robot.dm

@@ -587,7 +587,7 @@
 					O.show_message(text("\blue [M] caresses [src]'s plating with its scythe like arm."), 1)
 
 		if ("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src )
 

code/modules/mob/living/simple_animal/simple_animal.dm

@@ -268,7 +268,7 @@
 						O.show_message("\blue [M] [response_help] [src].")
 
 		if("grab")
-			if (M == src)
+			if (M == src || anchored)
 				return
 			if (!(status_flags & CANPUSH))
 				return
@@ -304,7 +304,7 @@
 				if ((O.client && !( O.blinded )))
 					O.show_message(text("\blue [M] caresses [src] with its scythe like arm."), 1)
 		if ("grab")
-			if(M == src)
+			if(M == src || anchored)
 				return
 			if(!(status_flags & CANPUSH))
 				return
@@ -467,4 +467,4 @@
 		var/obj/mecha/M = target
 		if (M.occupant)
 			return 0
-	return 1
+	return 1