Just look up. On bridges, buildings, trains, the backs of freeway signs, the tag is everywhere. It's an inspirational call to the "next" generation, a macho throw-up that conveys the adrenaline, irreverence and illegality of its creation. Most of all, it's cool. But the Houston Police Department's antigang task force doesn't think so. Last March, officers raided a legal graffiti show in a warehouse on the east side. Wearing all black with guns strapped to their legs, the officers said they were looking for "intel." But aerosol artists say the cops were really looking for Next, the most prolific graffitist in town. The task force was out of luck, though. Next was nowhere to be found.