Who has a big black moustache... smokes a big black cigar... and is a big pain in the neck to draw?
Does he wear glasses?
'Attsa right, you guess quick.
I don't know why I had so much trouble drawing poor Groucho, but I think it shows. I wanted to find a reference pose of him doing his walk, but I couldn't find any I liked.
So, now they're complete: