Two of Joan Crawford’s latter screen appearances were in “Straitjacket” (s. Robert Bloch) and lastly in “Trog” which some people think of (not me) as a big step down from her days in James M. Cain’s “Mildred Pierce.”
Sherlock Holmes actor Basil Rathbone’s last two appearances were “The Autopsy of a Ghost” (Mexican) and then “Hillbillies in the Haunted House” (billed under hayseed Ferlin Husky, country western singer).
John Carradine made it a point to take any role for a paycheck, no matter how bad. He was nominated for “The Grapes of Wrath” as a befuddled preacher and ended up doing movies like “The Astro-Zombies”, "Corpse Grinders", and “Billy the Kid vs. Dracula.” A film professor friend of mine told me once, “It is a good idea to make a movie about Billy the Kid. It is a good idea to make a film about Dracula. But it is not a good idea to make a movie about both of them in the same movie.”
John Carradine made all these grade-z movies with no artistic quality but was a champion of aesthetics apparently because he did artistic things--his last--he died because he never recovered from climbing the entire stairs of the Milan Cathedral to see the architecture of the massive structure..
The last movie for both J. Carrol Naish and Lon Chaney, Jr. was a Grade Z movie called ”Dracula vs. Frankenstein” in 1971 directed by cult cheese/sleaze director Al Adamson (who himself was later murdered and buried in wet cement in the den of his house).
For the last several years, directors knew that they had to get their scenes with Chaney done before 11 am because he would be drunk by then. I read somewhere that he had a phobia, a fear of running out of stored food (seriously).
Agnes Morehead, a member of the Mercury Theatre with Orson Welles, did a horror movie that was almost unmentionable it was so bad, and she ends up losing her head at the close of the movie.
Joseph Cotton ended up in forgettable films like “Baron of Blood” and “Lady Frankenstein" (two decades earlier in Cotton’s acting life, Ed Wood, Jr. forced him to attend his terrible play, “The Casual Company” and he told Ed, when pressured to say something nice about it, said, “I think it will go okay...” just to get Wood off his back).
Glenn Strange who often played the Frankenstein monster ended up being the bartender of the Long Branch saloon on “Gunsmoke.” To a lesser extent, George Tobias starred in a lot of films with stars like Gary Cooper and ended up being Agnes Cravitz’s henpecked husband..
As a horror writer I love these Grade-Z movies, no matter how bad, but there must be some built-in rule for actors that it is inevitable that towards the end of their career that they will end up doing movies that cult Horror/SF fans like a lot (people like me who like MST3000 perhaps) but standard movie fans don’t like very much.