Loner Outcast at high school starter pack

Loner/Outcast at high school starter pack; Usually eats lunch alone; Very rarely speaks. Never initiate conversations. Gets extremely shy when spoken to. Almost everyone sees him/her with a sense of pity. Sometimes made fun of behind one's back; Usually works alone unless forced to. Typically the last one to be partnered up. Either has no social media presence, or has one, but keeps it a secret from everyone at school; Never gets invited anywhere and never attends any after school activities