diff --git a/api.txt b/api.txt
index 8946ea8..85900ee 100644
--- a/api.txt
+++ b/api.txt
@@ -131,7 +131,7 @@ The mob api also has some preset variables and functions that it will remember f
     'self.owner' string used to set owner of npc mobs, typically used for dogs
     'self.order' set to "follow" or "stand" so that npc will follow owner or stand it's ground
     'on_die' a function that is called when mob is killed
-    'do_custom' a custom function that is called while mob is active and which has access to all of the self.* variables e.g. (self.health for health or self.standing_in for node status)
+    'do_custom' a custom function that is called while mob is active and which has access to all of the self.* variables e.g. (self.health for health or self.standing_in for node status), return with 'false' to skip remainder of mob API.
 
 
 mobs:register_spawn(name, nodes, max_light, min_light, chance, active_object_count, max_height, day_toggle)