As viewers learned last week, Matt Parkman has a problem on his hands. Or in his head, really.

His name is Sylar and he's stalking Parkman's brain, due to the body switch with Nathan pulled off on the May finale of Heroes.

In a new interview with TV Guide Magazine, Greg Grunberg previews how Sylar's presence will affect Matt (in the bedroom, apparently). A few excerpts:

On how Sylar will alter Parkman: [For example] he would normally make love to his wife and instead he’s extremely rough. Let’s just put it that way. There’s a scene that we shot and I have no idea whether they’re going to air it or not especially at 8 o’clock. Matt and Janice are getting down and it’s not Matt so she’s like, “Wow, this is amazing! What are you doing?”

On Samuel and his carnival: [Their objective is] to rope all of the main characters into the carnival. It’s a creepy idea when you think about it that these people who are running the carnival are people with abilities who are hiding out right in the open. It makes you not want to go to a carnival anymore. The county fair doesn’t look so friendly anymore!

On criticism of Heroes: A show like this is hard to maintain. You can’t please everyone all the time. We’re just hitting a great stride this year and bringing the characters back to the root of where they started. Like my character Matt does not want to use his powers. He just wants to have his life back and he can’t because this evil guy is in his head.

So it’s going back to, “How do I deal with the powers that I’ve been given?” That’s what was so magical about the first. The characters were discovering their powers, so it’s a rediscovery this year.

As always, we encourage readers to discuss the show in our Heroes forum.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.