diff --git a/api.lua b/api.lua
index 25d5d37..1c1f310 100644
--- a/api.lua
+++ b/api.lua
@@ -3,7 +3,7 @@
 
 mobs = {}
 mobs.mod = "redo"
-mobs.version = "20171222"
+mobs.version = "20171230"
 
 
 -- Intllib
@@ -61,6 +61,7 @@ local remove_far = minetest.settings:get_bool("remove_far_mobs")
 local difficulty = tonumber(minetest.settings:get("mob_difficulty")) or 1.0
 local show_health = minetest.settings:get_bool("mob_show_health") ~= false
 local max_per_block = tonumber(minetest.settings:get("max_objects_per_block") or 99)
+local mob_spawn_amend = tonumber(minetest.settings:get("mob_spawn_amend") or 1)
 
 -- Peaceful mode message so players will know there are no monsters
 if peaceful_only then
@@ -2834,7 +2835,7 @@ function mobs:spawn_specific(name, nodes, neighbors, min_light, max_light,
 		nodenames = nodes,
 		neighbors = neighbors,
 		interval = interval,
-		chance = chance,
+		chance = (chance * mob_spawn_amend),
 		catch_up = false,
 
 		action = function(pos, node, active_object_count, active_object_count_wider)
diff --git a/api.txt b/api.txt
index 3ec6908..4eb297b 100644
--- a/api.txt
+++ b/api.txt
@@ -1,5 +1,5 @@
 
-MOB API (18th October 2017)
+MOB API
 
 The mob api is a function that can be called on by other mods to add new animals or monsters into minetest.
 
@@ -13,6 +13,7 @@ The mob api is a function that can be called on by other mods to add new animals
     'mobname' can change specific mob chance rate (0 to disable) and spawn number e.g. mobs_animal:cow = 1000,5
     'mob_difficulty' sets difficulty level (health and hit damage multiplied by this number), defaults to 1.0.
     'mob_show_health' if false then punching mob will not show health status (true by default)
+    'mob_spawn_amend' defaults to 1.0 but can be set to 0.5 to half ALL spawn rates or 2.0 to double.
 
 mobs:register_mob(name, definition)
 
diff --git a/api_new.txt b/api_new.txt
index 15b87a3..ef0c4e3 100644
--- a/api_new.txt
+++ b/api_new.txt
@@ -1,6 +1,6 @@
 
-Mobs Redo API (last updated 18th Oct 2017)
-==========================================
+Mobs Redo API
+=============
 
 Welcome to the world of mobs in minetest and hopefully an easy guide to defining
 your own mobs and having them appear in your worlds.
@@ -546,6 +546,8 @@ External Settings for "minetest.conf"
                           multiplied by this number), defaults to 1.0.
    'mob_show_health'      if false then punching mob will not show health status
                           (true by default)
+   'mob_spawn_amend'      defaults to 1.0 but can be set to 0.5 to half ALL spawn
+                          rates or 2.0 to double.
 
 Players can override the spawn chance for each mob registered by adding a line
 to their minetest.conf file with a new value, the lower the value the more each