You know you’ve hit it big when Mariah Carey, Queen of the Holidays, asks you to sing with her for a holiday special. For Mariah Carey’s Magical Christmas Special, Ariana Grande joined Carey and Jennifer Hudson for a remix of her 2010 hit “Oh Santa!” from her album Merry Christmas II You. It landed on YouTube yesterday, and by the end of the day, it was already No. 2.