Mustached characters are mysterious non-canon characters that have facial features (most notably a mustache) and only appear in the animation ROMP.FLA.
When Sanford and Deimos are teleported by the mustached star, they are greeted by a group of four mustached characters, who direct them into a building. There are several more mustached characters in the building, who proceed to direct the duo to a star on the wall. The star then exclaims that their allies in purpose have betrayed them.
The mustached characters then close in on Sanford and Deimos, however the pair easily kill all of the mustached characters in the room with their M16, MP5 and Colt Revolver. In the next room, more mustached characters are easily killed by Sanford's hook and iron pipe and Deimos' unarmed attacks.
Upon crossing a bridge into a third room, Sanford and Deimos are startled when the mustached star bursts through the wall and exclaims that a betrayal upgrade is imminent. Six zombified mustached characters then walk into the room with signs, which they use to pierce and kill the duo.