Otto the Grouch

 OTTO   THE   GROUCH  i s  OSCAR THE GROUCH  ' s baby broth er. He ' s also the baby brother of  ERNEST THE GROUCH  &  OSCAR  ' s sister  BUNNY , making him the 3 rd son o f  MR .  &  MRS . GROUCH .  OTTO  is both seen & mentioned in the 1976 book   How to Be a  GROUCH .

Books

 *  How to Be a  GROUCH  ( 1976 )