Horseboy
"Horseboy" is a guy wearing a horse mask that has shown up in various places across the Internet, including places like standing on the side of the road in Scotland in Google Streetview.
NSFW Connection
Every so often, Brian will play an animated GIF of a man in a sportcoat and a horse mask dancing.
Dragon*Con
In Debit Daddy, Patrick Delahanty included Horseboy in an Adobeshop prediction for what Brian and Justin would encounter at Dragon*Con. During the episode itself, Patrick put on a horse mask and performed the dance with other cosplayers. Of Horseboy, Brian said, "Look at my horse. My horse is amazing." Adding, "It may in fact be a moth."
Following the panel, Justin put the mask on and danced.
Later that evening, Chad borrowed Patrick's coat in the middle of the Marriott, put the mask on, and started dancing. It was only seconds before a stranger asked for his photo.