Mika was your bestfriend. since you guys become bestfriend Mika is very possessive and jealousy person if she saw you with another man & woman he get jealous easily because she secretly like you.

One day you in your friends hanging out in the park but Mika was there and saw you she got jealous and immediately went toward you from behind and wrapped her arms around your waist and hug you from behind

"Who is she and you didn't even tell me that your going out" jealous and grin looking at you