Once heard never forgotten, the music of Xmas Lights can be a terrifying force.

The band's barrage of skull-pounding riffs, towering melodies and unsettling screams can leave the unsuspecting listener reeling under its unrelenting onslaught. But it can also be a thing of sublime, complex beauty. And there lies the band's unique appeal.

You just don't know what youre going to get.

"There is nothing more boring than predictable music," says the band's razor-witted and eloquent guitarist, James Gray-King.

"Verse, chorus, verse, chorus, middle eight - I know some people have done it beautifully, but not us. We get bored too easily. We like to push ourselves musically.

"Our theory is there must be so many incredible riffs out there that have never been played, as people stick with what they already know."

James, who divides his time between Oxford's Cowley Road and Swansea, and previously served with Oxford band Near Life Experience, met band mates vocalist Marco Ruggiero, from Bladon, near Woodstock; keyboard player and sample-meister Umair Chaudry, from Banbury; bass player Simon Tierney, from Didcot; and drummer - and Oxford University mathematician - Dave McDonald, through a series of adverts for musicians. Recruitment took place in the pub as much as in the studio.

"We went through the process of drinking together, to see if we could get on as mates," James recalls.

"And, apart from me, we come across as a pretty conservative bunch. We are all pretty opinionated and have a self deprecating sense of humour."

Which is why, when it came to choosing a location for their photo shoot, they decided to take to the river for some Oxford-style punting.

"We wanted to distance ourselves from the clichs of metal," James explains. "Anyway, there are only so many times you can see a picture of five grumpy-looking blokes posing in an alleyway."

So, if it's not metal, what is it? Labels like hardcore, electronica, prog, post rock and ambient have been bandied around, in a futile attempt to pigeonhole the band.

James adds: "Our music can be ridiculously heavy, but it can also sound like Pink Floyd or Mogwai."

So where does this heady brew come from?

"If we like listening to one part that someone plays, that will form the basis of the song.

"We just think 'what would be the coolest thing that could happen next?' "In 20 minutes of messing around there might be 30 seconds of genius. The trick is to pick those 30 seconds."

The band, who have two hours of material they can dip into, convene at the Zodiac tomorrow, headlining a night of live music, being staged by the team behind BBC Oxford's Download local music show.

The Download Live night, hosted by charismatic presenters Tim Bearder and Dave Gilyeat, also features Foals, And No Star and Remember The Flood.

But it's Xmas Lights who are driving local scene-watchers to distraction. The band also have a few surprises in store, which include turning up in white suits and having moving images projected on their bodies.

Doors open at 7pm. Tickets are £5 in advance or £6 on the door.