hardcore dancer
A hardcore dancer is a person usually in their teens who has immense quantities of angst due to listening to hardcore and emo music. 

These teens will go to concerts wearing tight pants, and tight jeans. Instead of the usual mosh pit, they will take play in hardcore dancing. This consists of swining their arms and legs around in a random fashion attempting to look they like are fighting invisiable enemies all around them.

Hardcore dancers are known to look like idiots, but seem to not care.
Chad demanded that everyone in the mosh pit beat up all hardcore dancers.