Grimm Grimm

It's a close encounter of the rodent kind on Grimm.

During a special Thursday airing (10/9c on NBC) of the fairytale-laced cop drama, Nick (David Giuntoli) gets called in to investigate the grisly death of a high school music teacher. At the school they encounter Roddy, an outcast with whom Nick needs help to question.

Is TV too gory?

"Nick is new to this world," Silas Weir Mitchell, who plays Monroe, tells "When it's discovered that someone that he's investigating, or even just questioning, is from the creature realm or is a human that is descended from creatures, he still doesn't have all the tools necessary for addressing that situation. Grimms and creatures are natural enemies, so he has to be very delicate with how he addresses the situation, because as far as they're concerned, he's going to kill them."

Enter Monroe, a wolf-like blutbad, whom Nick turns to to relate to Roddy. "In the case of Roddy, it's discovered that he's an outcast. He's a troubled kid at a fancy, hoity-toity high school," says Mitchell. "The kids kind of gang up on him and he's suspected of using extreme methods of getting back at his peers who are ostracizing him. And he has a secret that is revealed."

NBC orders a full season of Grimm

But what does this all have to do with rats and the Pied Piper tale? Check out this exclusive clip of the first minute and a half of "Danse Macabre":

Poor, poor music teacher! We don't know if Roddy is really behind this (and by the way, we love the reference to wrestler "Rowdy" Roddy Piper), but we're also suspicious of that Cheshire Cat person in the rave.

Be sure to also check out Grimm at its regular airing, Fridays at 9/8c on NBC.