From Muppet Wiki

Mordicus is the Grouch character on 1, Rue Sésame, the first French co-production of Sesame Street.

Mordicus is a blue creature with ears, a nose and big black eyebrows who lives in a trash can. He is a little cynical and very energetic, full of life and enthusiasm. He has a habit of popping up unexpectetly from sewers or caves, which causes a lot of confusion among his neighbors. He loves old apple leftovers.

Mordicus plays the saxophone, and together with his fellow neighbors Dominé and Roger, he is a part of the resident singing group on Rue Sésame, the "Trio Sésame".

Mordicus is performed by Georges Mosca. Denis Demoulin occasionally performed his singing voice.