LIKE SO MANY acoustic duos, Tenacious D got its start playing open-mike nights down at the local club. Jack Black and Kyle Gass were different, though. Billing themselves as “The Greatest Band on Earth,” the two hardly svelte singer-guitarists took the stage with an unusual fervor, strumming and shrieking in a manner more akin to Queensryche than Simon and Garfunkel.

Tenacious D

Crocodile, Thursday, September 9

One more thing: Tenacious D’s sets were broadcast on national television.

That’s because “the D,” as their cult of fans calls them, are a mock-rock band, and Black and Gass are Los Angeles comedic actors who accidentally wrote a few “kick-ass” songs together. Their rise was swift. First a cameo in the 1996 Pauly Shore vehicle Bio-Dome. Then a couple of short films that were part of the HBO series “Mr. Show with Bob and David.” Last year, HBO enlisted Tenacious D to come up with half-hour episodes, and Black and Gass rocked. They wrote, performed, and acted in six segments, most of which started with the D playing amazingly intricate, usually self-referential songs, though the two were adept enough to sneak in nods to favorite bands (like Urge Overkill) and movies. Such was the case in the first episode, when Jack’s freak-out nearly caused the D to break up, leading to the lyrics: “Couldn’t split up Kato and Nash/Couldn’t split up Tango and Cash/This is our song of exalted joy/Because we are the band that kicks some ass.”

The episodes revolved around hilariously over-the-top plots, such as the time that Tenacious D ran into Satan, who threatened to steal the duo’s soul unless they could instantly play “The Greatest Song in the World.” Needless to say, they succeeded and beat Satan in a wrestling match to boot. Other highlights included the addition of a drummer, Sasquatch, who was subsequently fired because the D didn’t work as well as a power trio.

The phenomenally funny episodes led to inevitable Spinal Tap comparisons and to reported movie offers. It probably helps that Black’s been working in the biz for years, taking on TV roles in The X-Files and Northern Exposure and acting in films such as The Cable Guy, Dead Man Walking, and the forthcoming and highly anticipated John Cusack film High Fidelity. Gass, meanwhile, is beefing up his résumé; he claims to have a role in a yet-untitled Cameron Crowe film about the music business circa 1974. The D took time from their crammed schedules to chat with the Weekly in advance of their first Seattle appearance since an ill-fated stint at Bumbershoot’s Comedy Stage a few years back.

First things first: Is there a Tenacious D movie in the works?

Jack Black: There’s a lot of grumblings, mumblings, and movement in that direction right now, as we speak. The forces are aligning to create this thing we call a motion picture.

Will it screen at Sundance?

Kyle Gass: I’m more interested in the product placement. I want us both to be drinking Pepsi One.

Jack: Hee hee hee. Does that still exist? Didn’t that come and go already?

Kyle: I heard that in The Thomas Crown Affair, Rene Russo always has a Pepsi One with the label pointed toward the camera.

Jack: Do you think Rene Russo will read this?

Kyle: She has the best 45-year-old tail in town.

Tenacious D has opened for Beck and Pearl Jam. Would you ever consider opening for Guns N’ Roses?

Jack: I wouldn’t want to open for anyone ever again.

Kyle: Did you see VH-1’s Behind the Music on Metallica? Where they were talking about when they opened for Guns N’ Roses and Axl wouldn’t go on?

Jack: The fuckin’ guy from Metallica, what’s his name? Hatfield? He fuckin’ stuck his hand by accident into some pyrotechnics, and it burned his hand to the bone so they had to rush him to the hospital. Their set was only like 10 minutes before he burned his hand to a crisp. And the crowd was saying, “Let’s rock! C’mon, somebody’s gotta rock me, rock me!” And then Axl said, “I feel kinda shitty. I cancel.” Now do you think we wanna go open for that kind of bullshit? What if I stick my hand in the D pyrotechnics, and then Axl refuses to take care of the beeswax? Then I’d have to clop him on the chops. And I would.

Have you guys lived up to your musical potential in Tenacious D?

Kyle: No. I remember being kind of bummed out having to go to a gig because I knew we wouldn’t sound good.

Jack: I remember it in my mind being amazing and we were young and raw and fresh, and then I look back at the videotapes and I go, “Geez Louis Dreyfuss, we sucked!”

Kyle: I can’t believe we kept going.

Jack: I can’t believe anyone liked us. And the reason is: No one else is doing the two-man acoustic comedy. So we’re popular by default. Somebody had to fill the Cheech and Chong, Beavis and Butthead, Smothers Brothers. . . .

Kyle: We didn’t pay our dues. It was TV.