Syfy has released the first teaser trailer for Happy! and announced that Patton Oswalt (Agents of SHIELD) has replaced Saturday Night Live alum Bobby Moynihan as the voice of the title character.

The upcoming television series, which is based on Grant Morrison and Darick Robertson’s four-part comic book mini-series of the same name, stars Christopher Meloni (Law & Order: SVU) as Nick Sax. He was considered the best detective in the entire NYPD nearly a decade ago, but his life took a turn for the worse when he was kicked off the force. Now, an ever-cynical Sax makes a living as a hired gun and spends his days getting plastered and having meaningless sex. His path to redemption begins when Happy, an imaginary blue winged-horse, appears before him after a hit goes wrong.

“My life is an ever-swirling toilet that just won't flush,” Sax gloomily says to open the trailer. Looking worse for wear, the former and disgraced cop gargles alcohol in a cheap bar and, filled with self-loathing, stares at himself in a dingy bathroom mirror. Detective Meredith McCarthy (Lili Mirojnick) then appears and mentions Sax used to be a great detective. The front page of a New York Post from nine years ago is shown and features a photograph of a clean-shaven Sax – with a red circle around his head -- and its headline reads: “SUPERCOP'S WALK OF SHAME.”

After suffering a heart attack during a hit, the trailer concludes with Sax regaining consciousness in an ambulance and being startled by the sight of Happy the Horse on his chest. “Hey, can you see me?” an upbeat Happy asks a speechless Sax. “Here comes the fun.”

Moynihan was cast as the voice of Happy back in March and recorded the character’s dialogue for the pilot, but his commitment to the CBS comedy series Me, Myself & I forced him to drop out. During San Diego Comic-Con, Morrison, who serves as an executive producer and co-wrote the pilot, explained the reason for Moynihan’s departure to SYFY WIRE:

“Bobby was great when he did the reading. But as you know, he's got his own show now, and he just couldn't commit to it in the way that we hoped. But yeah, he did an amazing reading of the character. But Patton is a whole new thing. He's playing it in a kind of different style, and it's really interesting.”

Brian Taylor, who also serves as an executive producer and co-wrote the pilot with Morrison, told SYFY WIRE that Oswalt was his number-one choice from the start – as he always appreciated the kindness the comedian bestowed upon his 2009 action film Crank: High Voltage.

“Yeah, I was really pushing for him. I've been a fan of Patton for a long time.  He actually wrote a blog about, when his wife was pregnant with his daughter, going to see Crank 2 as a stress reliever -- in the theater -- and what an awesome experience that was. Like to me, it was one of the coolest things I've ever seen written about something that I did. So, I've always had this kind of Patton thing of just, 'Man, I like that guy. I like that dude. He gets it. He's alright.' And so, I just kind of thought he would be the ideal guy ... for this, kind of from the beginning. So I always kind of had it like, you know: 'Let's get Patton.'”

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Happy!, which its creator describes as “A Christmas Carol meets Pulp Fiction,” is expected to make its debut on Syfy sometime in 2018.