diff --git a/HyperNerd.cabal b/HyperNerd.cabal
index 989ef13..8b11ba1 100644
--- a/HyperNerd.cabal
+++ b/HyperNerd.cabal
@@ -108,6 +108,7 @@ executable HyperNerd
                      , Bot.Asciify
                      , Free
                      , OrgMode
+                     , Bot.Flip
 
   -- LANGUAGE extensions used by modules in this package.
   other-extensions:    OverloadedStrings
diff --git a/src/Bot/CustomCommand.hs b/src/Bot/CustomCommand.hs
index 4adb912..d4f85b1 100644
--- a/src/Bot/CustomCommand.hs
+++ b/src/Bot/CustomCommand.hs
@@ -12,6 +12,7 @@ module Bot.CustomCommand
   ) where
 
 import Bot.Expr
+import Bot.Flip
 import Bot.Replies
 import Command
 import Control.Monad
@@ -179,6 +180,8 @@ evalExpr vars (FunCallExpr "or" args) =
   fromMaybe "" $ listToMaybe $ dropWhile T.null $ map (evalExpr vars) args
 evalExpr vars (FunCallExpr "urlencode" args) =
   T.concat $ map (T.pack . URI.encode . T.unpack . evalExpr vars) args
+evalExpr vars (FunCallExpr "flip" args) =
+  T.concat $ map (flipText . evalExpr vars) args
 evalExpr vars (FunCallExpr funame _) = fromMaybe "" $ M.lookup funame vars
 
 expandVars :: M.Map T.Text T.Text -> [Expr] -> T.Text
diff --git a/src/Bot/Flip.hs b/src/Bot/Flip.hs
new file mode 100644
index 0000000..b0581b6
--- /dev/null
+++ b/src/Bot/Flip.hs
@@ -0,0 +1,72 @@
+module Bot.Flip where
+
+import qualified Data.Map as M
+import Data.Maybe
+import qualified Data.Text as T
+
+-- https://github.com/doherty/Text-UpsideDown/blob/master/lib/Text/UpsideDown.pm
+-- http://www.fileformat.info/convert/text/upside-down-map.htm
+flipText :: T.Text -> T.Text
+flipText = T.map (\x -> fromMaybe x $ M.lookup x table) . T.reverse
+
+table :: M.Map Char Char
+table =
+  M.fromList
+    [ ('\x0021', '\x00A1')
+    , ('\x0022', '\x201E')
+    , ('\x0026', '\x214B')
+    , ('\x0027', '\x002C')
+    , ('\x0028', '\x0029')
+    , ('\x002E', '\x02D9')
+    , ('\x0033', '\x0190')
+    , ('\x0034', '\x152D')
+    , ('\x0036', '\x0039')
+    , ('\x0037', '\x2C62')
+    , ('\x003B', '\x061B')
+    , ('\x003C', '\x003E')
+    , ('\x003F', '\x00BF')
+    , ('\x0041', '\x2200')
+    , ('\x0042', '\x10412')
+    , ('\x0043', '\x2183')
+    , ('\x0044', '\x25D6')
+    , ('\x0045', '\x018E')
+    , ('\x0046', '\x2132')
+    , ('\x0047', '\x2141')
+    , ('\x004A', '\x017F')
+    , ('\x004B', '\x22CA')
+    , ('\x004C', '\x2142')
+    , ('\x004D', '\x0057')
+    , ('\x004E', '\x1D0E')
+    , ('\x0050', '\x0500')
+    , ('\x0051', '\x038C')
+    , ('\x0052', '\x1D1A')
+    , ('\x0054', '\x22A5')
+    , ('\x0055', '\x2229')
+    , ('\x0056', '\x1D27')
+    , ('\x0059', '\x2144')
+    , ('\x005B', '\x005D')
+    , ('\x005F', '\x203E')
+    , ('\x0061', '\x0250')
+    , ('\x0062', '\x0071')
+    , ('\x0063', '\x0254')
+    , ('\x0064', '\x0070')
+    , ('\x0065', '\x01DD')
+    , ('\x0066', '\x025F')
+    , ('\x0067', '\x0183')
+    , ('\x0068', '\x0265')
+    , ('\x0069', '\x0131')
+    , ('\x006A', '\x027E')
+    , ('\x006B', '\x029E')
+    , ('\x006C', '\x0283')
+    , ('\x006D', '\x026F')
+    , ('\x006E', '\x0075')
+    , ('\x0072', '\x0279')
+    , ('\x0074', '\x0287')
+    , ('\x0076', '\x028C')
+    , ('\x0077', '\x028D')
+    , ('\x0079', '\x028E')
+    , ('\x007B', '\x007D')
+    , ('\x203F', '\x2040')
+    , ('\x2045', '\x2046')
+    , ('\x2234', '\x2235')
+    ]