Once upon a time, there was a beautiful little girl called Yasmin Sophia. She lived with her mummy and daddy and baby brother Isaac.
But once a month for five whole days, or more, Yasmin would be spirited away and replaced by a mini monster who went by the name of Steroid Monster.
Steroid Monster was a very hungry monster. She howled and howled whenever she wanted to eat. Steroid Monster liked to munch on Weetabix all day long and sometimes ate five in a day. She also liked toast with lots and lots of butter - but Steroid Monster's favourite dish was pasta with pesto.
Steroid Monster was a very, very, grumpy monster and spent a lot of the day moaning. She sometimes hid under the table and got very red in the face. Steroid Monster's favourite words were "I want, I want, I want...."
But Steroid Monster didn't understand why she was so grumpy and she also needed lots and lots of cuddles and love and lots and lots of love and cuddles.
Mummy and daddy were always happy when their beautiful daughter came back home again - no more monsters for another month. Isaac was relieved to have his sister back too. Steroid Monster was even worse at sharing than Yasmin was.