The group is called The Pizza Underground (instead of, say, The Velvet Pizzaground, The Velvet Underpizza or The Pizza Pizzapizza), and Culkin is responsible for vocals, kazoo and "percussion," which – in keeping with the spirit of the original band's rough-hewn style – is performed on empty pizza boxes.
The Pizzas have played one show, and their only recorded music consists of an eight-minute medley that includes "Papa John Says," "I'm Beginning To Eat The Slice," and "Cheese Days," which are parodies of "Stephanie Says," "I'm Beginning to See The Light" and "These Days," respectively.
(Completists/nerds will note that "These Days" is in fact a Jackson Browne song most famously covered by ex-Velvets vocalist Nico, and not a Velvet Underground song. For shame, Macaulay.)
If this "ex-child star cover band" thing is to become a trend, we'd like to see Frankie Muniz tackle some mid-period Bowie next. But make all the songs about sushi.