The Leprechaun Brothers

From Muppet Wiki

The Leprechaun Brothers are a singing group made up of the Swedish Chef, Beaker and Animal. None of them are particularly skilled with the English language, so they tend to mangle their songs.

The trio appeared on The Muppet Show in episode 520, where they sang "Danny Boy."

They also appeared in a mini-game for the Muppets Inside video game in 1996. The trio would "sing" a public domain song like "Camptown Races," and the player was challenged to guess the title of the song.