Crazy text allows you write crazy like ʇxǝʇ ʎzɐɹɔ :).
You can easily write any text and inverse the letters or even flip them.
Inverse works with anything you enter in the text field, however flip can only work with lower-case letters a-z and some extra characters like ?, !, comas, dots…
You can also use any font iPhone allows you.
So to conclude you can easily format and modify your text, save it for later or copy 'n' paste to your mails.