"...was it like...weird sculptures or splattery stuff or real art?" Again, most of what Hiro knows about art is gleaned from when art studios get smashed in the course of a monster movie. Also, he naturally thinks Sam has impeccable fashion sense (which doesn't mean much coming from a kid who owns maybe two pairs of pants).

The explanation is surprisingly benign, and well within what Hiro would consider a logical and rational response. So much so that he blinks a couple times and asks, without thinking -- "Sooooo not a newt, then."