By Lynette Rice
July 24, 2009 at 05:33 AM EDT

Let us count the ways Showtime ismerchandising Dexter, its serial killer drama! As revealed at Comic-Contoday, there will be animated “Dexter Early Cuts” on this fall,a special application for iPhones called “Dexter: The Game,” and(strange) action figures of all your favorite Dexter characters. “WhenI was shooting the pilot, I didn’t think it would come to this,”groused star Michael C. Hall during the show’s packed panel.

But it’s the new killer that seems to have the castmost juiced for its Sept. 27 season premiere on Showtime: John Lithgow joins the actionthis season as the “Trinity” killer, aka “the most successful serialkiller ever.” The thousands of Dexter fans who filled Ballroom 20 todaygot a sneak peek of Lithgow’s upcoming work, which, naturally, included a scene ofhim slitting the throat of a helpless brunette. Lithgow, who joined the panel along with the always charming Hall, amongothers, wouldn’t divulge much about his character. But he did joke thathis first victim was “High Commander Dick Solomon”—his memorablecharacter on the long-running sitcom Third Rock From the Sun. “Thischaracter has so many layers and colors,” he teased.

Family and a new baby will figure significantly in thefourth season—the teaser included scenes of a sleep-deprived Dexterfailing at his day job as a blood splatter expert—but Hall admittedit’s early yet to question whether the apple falls far from the tree.”The baby has yet to exhibit any signs,” Hall said. “It’s possiblythere, lurking.”

addCredit(“Dan Littlejohn/Showtime”)