diff --git a/scripts/magmasource.rb b/scripts/magmasource.rb
new file mode 100644
index 000000000..14f517fd1
--- /dev/null
+++ b/scripts/magmasource.rb
@@ -0,0 +1,65 @@
+# create an infinite magma source at the cursor
+
+$magma_sources ||= []
+$magma_onupdate ||= nil
+
+case $script_args[0]
+when 'here'
+    $magma_onupdate ||= df.onupdate_register(12) {
+        if $magma_sources.empty?
+            df.onupdate_unregister($magma_onupdate)
+            $magma_onupdate = nil
+        end
+
+        $magma_sources.each { |x, y, z|
+            if tile = df.map_tile_at(x, y, z) and DFHack::TiletypeShape::PassableFlow[tile.shape]
+                des = tile.designation
+                des.flow_size += 1 if des.flow_size < 7
+                des.liquid_type = 1
+                des.flow_forbid = true
+
+                mf = tile.mapblock.flags
+                mf.update_liquid = true
+                mf.update_liquid_twice = true
+
+                zf = df.world.map.z_level_flags[z]
+                zf.update = true
+                zf.update_twice = true
+            end
+        }
+    }
+
+    if df.cursor.x != -30000
+        if tile = df.map_tile_at(df.cursor)
+            if DFHack::TiletypeShape::PassableFlow[tile.shape]
+                $magma_sources << [df.cursor.x, df.cursor.y, df.cursor.z]
+            else
+                puts "Impassable tile: I'm afraid I can't do that, Dave"
+            end
+        else
+            puts "Unallocated map block - build something here first"
+        end
+    else
+        puts "Please put the game cursor where you want a magma source"
+    end
+
+when 'delete-here'
+    $magma_sources.delete [df.cursor.x, df.cursor.y, df.cursor.z]
+
+when 'stop'
+    $magma_sources.clear
+
+else
+    puts <<EOS
+Creates a new infinite magma source at the cursor.
+Arguments:
+ here - create a new source at the current cursor position
+        call multiple times for higher flow
+ delete-here - delete the source under the cursor
+ stop - delete all created magma sources
+EOS
+
+    if $magma_sources.first
+        puts "Current magma sources:", $magma_sources.map { |s| " #{s.inspect}" }
+    end
+end