Headbang is an emote that all players can use, as there are no requirements. It is automatically awarded to a character when they create an account. The emote resembles headbanging as people in a rock concert would.
If the player did the headbang emote and then clicked a regular/dead tree, it appeared as if the player were chopping the tree down with his/her head. This has since been fixed.
A glitch sometimes occurs where a player's head is stretched as he or she performs the emote facing a wall.
Before the graphical update, the player's right arm would move forward along with the head. When facing a wall, it appeared as if the player was pushing his own head into the wall.
Before the implementation of the Emote delay system, It was possible to couple the headbang emote with the spin emote. This made the player spin and headbang momentarily before the two cancelled each other out.
With the edition of the EoC and updated models the player now holds up fingers when doing the emote.