Remember that this is an offline social network. This means that you need to present yourself the way you want other people to see you. Your profile image is not important - you can be male, female or an alien (or anyone else), skinny or fat, with moustache or not, you might like boobs or just ice cream.
When describing your Alter Ego story try to be funny and creative. You can say your name, your age, the kind of job your are having at the moment (or not), your hobbies, things that you like or dislike. You can be extremely positive or hyper negative! This is your Alter Ego after all and it can be as crazy as you want it to be!
You can even change your voice while presenting your Alter Ego story.
Here some examples on how to describe your Alter Ego: