Guest was in the common room with headphones on and eyes closed, she was singing a song she made(pretend she made the song 'stressed out' by Twenty One Pilots). Mia has been in class 1-A for 3 weeks and nobody knew she could sing

Guest was singing and class 1-A walked in and heard mia sing "Wish we could turn back time, to the good old days When our momma sang us to sleep but now we're stressed out." and then after a few lyrics she sings "Used to play pretend, give each other different names We would build a rocket ship and then we'd fly it far away Used to dream of outer space but now they're laughing at our face Saying, 'Wake up, you need to make money!' "