Macaulay Culkin's middle name WAS Carson. Apparently, he wasn't a fan so he took to his website to announce that he was going to let his fans pick a new middle name for him.
Some really close contenders were:
SharkWeek
TheMcRibIsBack
PublicityStunt
Kieran
But the one that truly won fans over was "Macaulay Culkin."
So, Mack's new name will read: Macaulay Macaulay Culkin Culkin
You're welcome :)