They are aggressive, they use bad language and are hilarious to look at!
In Estonia they have a nickname "rullnokk":
Little summary about that "subculture" and introduction to the film below:
Here is Rasmus Merivoo's film called "Tulnukas," the Estonian word for "alien". In just 22 minutes, it caustically deconstructs the rullnokk mindset, simply by reflecting. Film can be seen with English subtitles at Google Videos: