With special tweets you can compose tweets that are altered in various ways. You can undeline, strike or overlay your text. You can also mix up the words in a tweet and reverse all the characters. There are also some additional ways to change your tweet, like random mix up of lower case and upper case letters, upside down text, and some widely available special characters. You can create a tweet, pick the version you like and click the send button if you want to actually tweet the text. Works only for character a-z,A-Z-,0-9

Do not use this tool too often, or you may start to lose followers!