Red Guy is one of the main members of the Don't Hug Me I'm Scared band, along with Duck Guy and Yellow Guy. He resembles no known creature or thing besides spaghetti or a mop. He left the band after their song "Computers" to go to university.
He played a major role in their song "Dreams", he was able to go back in to to fix everything that had gone wrong recently. In "Dreams", he was with other people of his species in suits for a majority of the song, before finding the sound and visual effect board controlling the episode in which Yellow Guy is still trapped. Red Guy started pushing the board's buttons, glitching the Lamp into other singers they had featured in previous episodes and many other new singers that we haven't seen them do a collaboration with, until Roy puts his hand onto Red Guy's shoulder, shocking him. Red Guy then found a plug connected to the board and pulled it. This sent him back in time to their first song "Creativity", it also magically changed the puppets into their favorite colors, turning Red Guy blue, Yellow Guy green and Duck Guy red. This action moved the calendar from June 19 to June 20 too, finally moving forward in time past Father's Day.
Red Guy's Wiki
Exclusive interview with It's Nice That