When Karl gets into character, he can fool even his buddies on the show - including 10-year-old Maya Goldman of Columbia. Maya alternates the role of Cindy Lou Who with another girl, Lexie DeBlasio.
"It's weird," Maya says, "He can be very wacky. But when he has makeup on, and when he's being mean, it's hard to look him in the eyes."
The cast and crew have spent the past two weeks in Baltimore fine-tuning every aspect of the production. Once the ingredients come together and the show is set - much like a Jell-O mold - the performance will be recorded in minute detail, down to the pattern of makeup marks on each character's face.
After The Grinch leaves Charm City, the show will go to Boston for six weeks. By then, Christmas will be over, and the show will shut down temporarily. But, during the 2009 holiday season, Broadway Across America hopes to have four productions of the Grinch running simultaneously throughout North America: on Broadway, in Los Angeles, in Toronto and this touring version. With the exception of the different casts, the productions will be identical to the one finalized here.
"It's crucial to select the right city where a national tour will kick off," O'Brien says.
"There are cities where birth is comfortable, and cities where birth is compromised. Baltimore is a gorgeous place to launch a tour. It's still family-oriented, with a community spirit. There are all these problems to work out, and you want an audience that will be receptive and sympathetic.
"You struggle and struggle and struggle. But once a show solidifies, once it is set, oddly enough, it maintains itself. Once a show is right, it never is wrong again. And then children can have that kind of experience I was talking about earlier."
Indeed. Child labor laws require that young actors be double-cast, and during a recent rehearsal at the Hippodrome, the "white cast" of children watched the "red cast" rehearse. In the final scene, a giant, beribboned wreath descends from the ceiling. All of the Whos - plus the now-reformed Grinch - gather inside it.
It's a tricky bit of stage business, because everyone has to get to precisely the right place at precisely the right moment, without missing a note, and without getting clunked on the head. The red cast is the first to give it a shot.
There are several false starts. Then, all at once, everything clicks into place. Almost effortlessly, it seems, a picture forms on stage - and it looks exactly like an illustration from the book.
