diff --git a/contrib/plugins/cowsay.sh b/contrib/plugins/cowsay.sh
new file mode 100755
index 000000000..71505fef6
--- /dev/null
+++ b/contrib/plugins/cowsay.sh
@@ -0,0 +1,37 @@
+#! /bin/sh
+
+maybe_cowsay()
+{
+    cowsay || cat <<EOF
+ _________________________________
+< Please install 'cowsay' program >
+ ---------------------------------
+        \\   ^__^
+         \\  (xx)\\_______
+            (__)\\       )\\/\\
+             U  ||----w |
+                ||     ||
+EOF
+}
+
+# Eg. {"jsonrpc":"2.0","id":2,"method":"getmanifest","params":{}}\n\n
+read -r JSON
+read -r _
+id=$(echo "$JSON" | sed 's/.*"id" *: *\([0-9]*\),.*/\1/')
+
+echo '{"jsonrpc":"2.0","id":'"$id"',"result":{"dynamic":true,"options":[],"rpcmethods":[{"name":"cowsay","usage":"<string>","description":"Have a cow, man!"}]}}'
+
+# Eg. {"jsonrpc":"2.0","id":5,"method":"init","params":{"options":{},"configuration":{"lightning-dir":"/home/rusty/.lightning","rpc-file":"lightning-rpc","startup":false}}}\n\n
+read -r JSON
+read -r _
+
+# eg. { "jsonrpc" : "2.0", "method" : "cowsay", "id" : 6, "params" :[ "hello"] }
+while read -r JSON; do
+    read -r _
+    id=$(echo "$JSON" | sed 's/.*"id" *: *\([0-9]*\),.*/\1/')
+    params=$(echo "$JSON" | sed 's/.*"params" *: *//' | tr -d '[{}]"')
+    echo '{"jsonrpc":"2.0","id":'"$id"',"result":{"format-hint":"simple","cowsay":"'
+    # FIXME: lightning-cli does not unescape \\, so we replace with an L.
+    printf "%s" "$params" | maybe_cowsay | sed 's/\\/L/g' | sed ':a;N;$!ba;s/\n/\\n/g' | tr '\012' '"'
+    echo '}}'
+done