As part of the New York City underground scene in the early 1990s, Prong and Helmet carved a niche of heavy metal that forged a path others tried to emulate but few could replicate. The Alamo City, and the White Rabbit in particular, created its own underground scene in the 1980s and '90s, one that definitely couldn't be copied.

After all, there can only be one Heavy Metal Capital.

Whether that moniker continues to be appropriate, or even accurate, in 2018 is always up for debate. But on Friday night, the two scenes joined forces when Prong and Helmet co-headlined San Antonio's most well-known underground venue.

The name may have changed to Paper Tiger in 2016. But the dark, dingy atmosphere and general-admission conglomeration of sweaty metalheads uniting for the love of their favorite bands remains the same. In essence, it's a venue Prong and Helmet could appreciate. And the New York duo expressed their gratitude by rocking the Tiger to its core.

Catching some off guard, the bill only featured those two acts. No local bands or support of any kind. And even though it was a Friday, Prong went on stage at a ghastly early 8:30 p.m. -- a half hour after the gates opened. It may not have been quite as early as Prong's 12:30 p.m. set four years ago at Knotfest in San Bernardino, California. But hey, that was a three-day festival of more than 50 bands. Somebody had to go on first.

In this case, Prong was rarin' to go from the start, even if fans were still arriving -- and paying the admission fee -- while Helmet was into its set. Taking pride in having released five albums in the past six years (though he told the crowd it was six for six), Prong singer/guitarist Tommy Victor, by far the only remaining original member of the trio, is touring in support of Zero Days. Mixing two new songs, including show opener "Forced Into Tolerance," with classic staples "Prove You Wrong" and "Beg to Differ," Victor joined bassist Jason Christopher and hair-whirling drummer (and Selena T-shirt wearing) Art Cruz into pulverizing the Paper Tiger with its East Coast brand of metal.

Victor, who told ATM in 2016 he preferred playing the older, more commonly known tunes because, "I don't like confusing people in a live situation" (listen to interview here), also had confided in ATM that he couldn't quite remember ever having had a great show in San Antonio. In 2014, Victor went so far as to say his most prominent memory of the Alamo City was "that bad barbecue pit by the White Rabbit."

Though Prong has visited a few more times since that recollection in large part to recent records X: No Absolutes, Ruining Lives and Carved Into Stone -- and even though the pit of a different kind is still there - Friday's gig was another chance for San Antonio to make amends in Victor's mind. At one point, he told the crowd to "Wake the fuck up" before adding with a smile, "Come on, this is San Antonio!" Surprisingly, multiple efforts to incite mosh pits yielded only slight activity on tracks such as "Unconditional" and "Cut and Dry" (ATM footage below), through no shortage of effort by Victor and Christopher. In the crowd's defense, that may have been partly due to the fact a flashlight would have better aided at times their view of the band in the dark confines of the Tiger, let alone to avoid blindly crashing into one another.

Recent tunes such as "Ultimate Authority" meshed with mainstays "Whose Fist is This Anyway?" and traditional finale "Snap Your Fingers, Snap Your Neck" (ATM Facebook Live footage of both available here). But before you knew it, the clock had struck 9:30 p.m. on a Friday night. And Prong was done.

That meant Helmet was going on as a 10 p.m. headliner. Like Victor, singer/guitarist Page Hamilton is the only remaining original member of his band. Though Helmet's style varies from Prong's, both bands influenced their city's scene in a big way.

Helmet, of course, broke out of the underground aura in 1990 thanks to its 1992 MTV smash video "Unsung." The slightly smaller, though no less significant, success of 1994 album Betty has also enabled Helmet to exist 25 years later, outlasting the video channel  -- at least in the form we all came to know and love before "Real World" and "Jersey Shore" -- that helped spawn the group's mainstream exposure.

Admittedly, a 10-hour-plus stint without food rendered one person to depart halfway through the set, prior to the scheduled penultimate performance of "Unsung" (setlists in slideshow). Helmet doesn't come around as often as Prong, which made that necessity unfortunate.

But for at least one night, two of New York's best from the subway level infiltrated South Texas' underground scene with a double jolt of metal. Who cares if it's "nu metal," "hardcore metal" or metal that melts your mother's face off? Just call it intense metal, any way you slice it. Even if it ended earlier than some headlining acts begin.

Who knew there was a curfew in the underground too?