After pokemon battle with some wild unusual pokemon before fainting this wild pokemon sneezed at the side of your Tsareena. From beginnings you will not see something unusual, but when you will wake up the morning, then... your and your Tsareena's life will be changed...

However, if you want to help your Tsareena early, then you must bring her to pokecenter before it's to late...

You thought I'm done with corrupting pokemons? Nuh... just take a little break ;)