Mariah Carey Star of Million Dollar Bat Mitzvah

5/7/2016 7:25 AM PDT

Mariah Carey was the headliner of her manager's daughter's Bat Mitzvah ... but someone's got to tell her the meaning of "mazel tov!"

Mariah made a grand entrance into 1 OAK in WeHo Friday for Mishka Bulochnikov, the 13-year-old daughter of Stella.

The event was insane ... a 500 lb chocolate and red velvet cake, mini Kanye from Jeff Beacher's Madhouse, a Bentley golf cart which Mishka got as a present, a DJ from Power 105 ... but the thing is ... it cost hundreds of thousands of dollars to rent the club out on a Friday night.

Kids ... they're expensive.