"Santa Claus is On His Way" is the song that introduces the character of Mr. Hankey in the Season One episode, "Mr. Hankey, the Christmas Poo". This song is included on the Mr. Hankey's Christmas Classics album.
His son Cornwallis Hankey sings the song to hobos in South Park: The Stick of Truth when on display to them.
In the Season Twenty-Two episode "The Problem with a Poo", Mr. Hankey sings the song while sewing a Santa outfit.
Background
When Kyle Broflovski keeps seeing Mr. Hankey appear to him in his bathroom, he does not want to believe he is real. Mr. Hankey sings this song to convince him otherwise.
Lyrics
Santa Claus is on his way
He's loaded goodies on his sleigh
To drop them off on Christmas Day
And I'll say 'Howdy-ho'
Folks will gather 'round the fire
sing a song, stroll the choir
Pretty soon they'll all retire
And I'll say 'Howdy-ho'
I hope that Santa comes real soon
I've been waiting for some we...