They are three unknown alternate dimension creatures that made appearances on that dimensions' version of "Saturday Night Live". The announcer couldn't pronounce their name, so basically all information about them is completely unknown.
They were left unnamed because Justin Roiland (who was voicing the announcer of "Saturday Night Live") didn't know what to call them. So in the recording studio, he just said "I'll get back to that one" and they just decided to use that in the final cut. 
- Piece of Toast – A sentient piece of toast.
- Two Guys with Handlebar Mustaches – A basketball player and a Buddhist that sport handlebar mustaches.
- Man Painted Silver Who Makes Robot Noises – This character is a parody of Chris Parnell's SNL character Kevin Aquarius.
- Garmanarnar – An insectoid.
- Hole in the Wall Where the Men Can See it All – A sentient gloryhole in the wall.
- Bobby Moynihan – This version of Bobby Moynihan has been on Saturday Night Live for 25 years. Rick comments to Morty that Bobby Moynihan and Piece of Toast hate each other due to some "creative differences".