It's hard to imagine that it's been 25 years since a bunch of Virginia Commonwealth University students decided that the best chance they'd have at getting national artistic attention would be to dress up like a bunch of sci-fi monstrosities and perform ear-bleeding thrash metal, exposing their stunned audiences to all sorts of visually obscene spectacles. Defying all logic, the over-the-top theatrics of Richmond's Gwar have only intensified throughout the decades, increasing the numbers of its cult following. Gwar is sure to produce plenty of gloriously tongue-in-cheek rockness on its latest gore tour — in support of its 11th album, “Lust in Space” — when it performs at the National on Friday, Oct. 23, at 7 p.m., $18-$21.