It's hard to resist dressing up as Groucho. He is universally recognized and the makeup is pretty easy to do. I've done it myself in younger, more hirsute days. I won the Halloween costume contest at the children's hospital where I was working at the time.
Over at
The Marx Brothers Council of Britain blog, Matthew Coniam unleashed a mystery on the blogosphere in the form of a photo of someone disguised as Groucho. The photo was used on the cover of CD of Groucho's radio performances.
Tom (sorry--I have no additional identifying information), an astute reader of Matthew's blog, solved the mystery. The photo is of famed photographer Alfred Eisenstaedt, and Tom had seen it before in the book
Life Goes to the Movies.
A little Googling on my part uncovered the article,
"Speaking of Pictures", subtitled "LIFE photographer gets made up to look like seven other people," in the September 26, 1949 issue of Life. The Paramount makeup artist who transformed Eisenstaedt into characters ranging from Sampson to Victoria Lake noted that Groucho was the easiest.