It’s a Tuesday night in The Black Heart, a rock bar whose none-more-black aesthetic - a spade sign above the door, and many of its regulars equally darkly attired - is undeniably at odds with the rest of Greenland Place, the unassuming, magnolia-bricked street on which it’s hidden away. Upstairs in the bar’s live music room, the temperature is rapidly reaching the kind of level for which the Met Office issue health warnings. Eat Me frontman Jamie Warnes is the most appropriately-attired person in the room as he takes to the stage wearing a tennis-style headband, although you get the sense he’d probably have worn it regardless of the weather conditions.

Such garments might look ridiculous outside of major sporting events, but this sartorial choice only feeds into the sense of charming chaos that Eat Me bring to their live show – their bouncy pop rock taking ‘Pinkerton’-era Weezer and putting it through a sneering, undeniably British ringer. And while at any other show it might be considered outré, the prevalence of silly string in the air only adds to the party atmosphere. Yeah, about the silly string…

Turn back the clock by three hours and the thermometer by about twenty degrees, and the three members of tonight’s headline act, Puppy, are in fine form as they sit among assorted gig bags, boxes and cables that constitute the pre-soundcheck landscape of any live show. Drummer Billy Howard – strikingly handsome in a 90s boyband sort of way, with gelled curtains and oversized tracksuit bottoms to match – is hand-folding ‘hymn sheets’ to go in the Puppy-branded tote bags that the band will be handing out to attendees at tonight’s EP launch, along with Puppy-branded lighters, Puppy-branded balloons and, yes, cans of silly string.

Much like Greenland Place itself, Puppy don’t exactly look the part – and perhaps that’s part of their appeal. Bassist Will Michael, who I imagine is the tallest person any of his friends know, is wearing the same Aaliyah t-shirt and backwards baseball cap he’ll wear on stage later. If Howard represents the clean-cut side of 90s pop culture, then Michael is its grungy, Kevin Smith-directed counterpoint. Bridging the gap between the two is guitarist, vocalist and generic alchemist Jock Norton.

There’s an easy, unforced dynamic between the three friends as they explain that tonight’s launch, for new EP ‘Vol II’, represents the end of their current chapter. The songs are written, recorded and released and their sights are already on the next batch. And what songs they are. Puppy are that rarity: something truly unique. 90s alt rock – Jock name checks Weezer’s blue album as a big (and unsurprising) influence on his songwriting – seamlessly melded with huge, unmistakably metal riffs. He cites Smashing Pumpkins as the standout demonstration of the potential for combining traditional, melodic songs with jagged, heavy guitars. “I came from a more indie background, whereas Billy was in a doom metal band,” he explains, describing a desire to combine those two worlds.

Norton’s a calm and engaging presence, talking passionately about the music the trio grew up on and the incredible opportunities with which 2016 has presented them – today’s release show, playing to a huge tent at Download, and their forthcoming tour with Sorority Noise; Howard is infectiously enthusiastic – a sparkle in his eye as he jokes around at every opportunity. “We take our music seriously,” he points out, “But we don’t take ourselves that seriously.” A statement backed up by his immediately branding the band’s sound as “super-duper heavy”, a childlike non-adjective which is somehow infinitely fitting.

Michael, on the other hand, is a conversational sniper – he rarely says a word but when he does, it’s straight to the point and usually hilarious. As we discuss the wider world’s continuing aversion to any metal which looks to the past with anything other than an ironic side-eye (Norton: “The Darkness were ironic… weren’t they?”), the subject of L.A. pastiche-metallers Steel Panther comes up. Michael suggests the band’s next move might be to adopt “wigs and spandex”.

Taking nothing for granted, Puppy talk of taking it one step at a time and appreciating the opportunities presented to them. There’s no pretension here, no delusions of grandeur or bold, media-trained statements about changing the world – just three remarkably inspired musicians writing songs that sound like nothing else out there, and having a great time doing it. Speaking of which…

As the collective perspiration of a hundred people causes silly string to start peeling off the ceiling, the room fills up even more – with both people and the aforementioned Puppy balloons – for newcomers Big Spring, who are an interesting prospect to say the least. Prodigious former Empress AD guitarist Ollie Loring has foregone the instrument altogether, opting to focus on singing – his new persona equal parts Chris Cornell and Brandon Boyd – while younger brother Alex still displays the kind of complex and creative bass-playing for which their former outfit were known, but in a much more restrained way. Tighter than an Olympian’s leotard, the band’s musical chops are unassailable. Gargantuan riffs, evocative of early-90s stoner legends Kyuss, spiral over Chris Steele’s pounding, Bonham-esque drums. There’s a lack of consistency among the quality and feel of their songs – perhaps a result of their relatively recent evolution – but for a band still counting their live appearances on one hand, this is impressive stuff.

Puppy, however, are on another level altogether. That three people can make so much noise is incredible all on its own; that they’re able to do so while giving equal space to their multitude of competing influences and while forging such a unique identity is downright thrilling. Norton’s glee at the enthusiasm of the sweaty throng is plastered across his face throughout their entire set, as tracks like ‘Do It Again’ are greeted like the instant classics they so clearly are.

Although much more at home in this cramped venue than they were on the much larger stage of Download, they’re not quite the finished article yet. But even when the set veers into the shambolic – an attempt to recreate the triple-guitar-no-drums attack of the brooding, atmospheric EP closer ‘Here At Home’ is restarted when it becomes clear that one of their guitars is violently out of tune – it’s impossible not to root for Puppy, so genuine is their enthusiasm and original their proposition. And as proceedings are brought to a close with the bludgeoning, Pantera swagger of Vol. II opener ‘Entombed’, there’s not a single head left un-banged.

If Puppy can build on both the musical promise and the audience devotion on display tonight, we could be witnessing the birth of something very special indeed. It’s not indie, it’s not metal, and there are no wigs or spandex. Who needs irony when you’ve got songs this good?