"Don't do a horror film unless you're the monster. Horror audiences come to see the villains, and they come back again when those villains are in the sequels," wrote The Economist magazine, listing things an actor should never do.
In India, many of the best-known Indian "villains" got into cinema hoping to be the hero. Things didn't go to plan and they spent their screen-time plotting fantastic heists and murders, eyeing the heroine and getting beaten up. With some notable exceptions, like Vinod Khanna and Shatrughan Sinha - villains turned heroes - this was the norm.
What about monsters then?
In India, the movie monster became a staple of horror films made by a group of brothers called, simply, the Ramsay Brothers. Five of the seven brothers are still around, and one of them, Shyam, is still quite active.
Between 1972, when they made their first proper movie Do Gaz Zameen Ke Neeche, literally "six-feet under", and 1994, when they made their last big movie, Mahakaal, the Ramsay brothers churned out movie after B-grade horror movie.
The tropes were more or less consistent, the quality of the acting veered between good and poor depending on who they managed to sign on, but the production values were remarkable, considering the constraints. They haven't aged well though, it has to be accepted.
They worked on incredibly low budgets at times, treating the process like a business: the income must justify the outlay.
There were no compromises with the monsters though, always the best part of their movies.
And no-one better than Anirudh Agarwal - the man synonymous with their movies, with a cultish following among cine-lovers. He acted in only three Ramsay films, playing a monster in two of them.
He went under the screen name Ajay Agarwal back then. By the time he acted as Babu Gujjar, who brutalises Phoolan Devi in director Shekhar Kapur's Bandit Queen (1996), Agarwal was using his own name.
In many other mainstream Hindi films, like Mela (2000), as well as a smattering of Hollywood films that needed some sort of a wild, monstrous "Indian", Agarwal did his menacing with aplomb.
But it was as Saamri, the devil-worshipping, corpse-eating monster in the Ramsays' biggest hit Purana Mandir (Old Temple) that Agarwal left the biggest impression.
Chatting with me, he clarified that he wasn't seven-foot tall as is popularly believed, but only six-four or six-five.
The camerawork, rudimentary but imaginative, made him look taller and bigger. But what of Saamri's face, which must have scared the bejesus out of viewers in those old, dingy single-screen theatres in metros and non-metros of the time?
"I have such a face - they (the Ramsays) didn't even need to put make-up on me. My face… I became a horror face for everyone," he says.
Shyam Ramsay, who directed most of the Ramsay films with his brother Tulsi, adds, "Anirudh had a very different face, even without makeup. If you see him today, if he walks on the street, people will turn around and look at him. He was perfect for us."
He certainly was.
Born in 1949, Agarwal was a middle-class boy from the town of Dehra Dun - only much taller than his peers.
He went on to graduate as a civil engineer in 1974. At university, he was active in student politics, sports and, of course, acting.
He took up an engineering gig in Mumbai (then Bombay), but the acting bug stayed. At one time, when he was taking a break due to ill-health, someone told him he should go speak to the Ramsays.
"When they offered me the film (Purana Mandir), I left my job. I was desperate to become an actor, and this was a chance. So I took it up. Since I was interested in films, and I thought I would get more chances, I changed my career," says Agarwal.
"Then I did two-three films with them in a row. My character in Purana Mandir was called Saamri, and then next year they made 3D Saamri. The character had become popular and the movie was a hit, so they tried to do another film with me."
Purana Mandir was a super-hit, but the 3D effort wasn't successful. Agarwal later made Bandh Darwaza in 1990 with the Ramsays, which made money again.
But there was not enough work coming his way, and he went back to being an engineer. Later, Agarwal acted in a few episodes of a horror show the Ramsays made for television.
He was last seen in Wilson Louis's Mallika (2010), playing a character called Saamri again. That movie sank.
A wonderful, soft-spoken man, Agarwal is polite to a fault. He is disarmingly candid about his appearance. And where he has been left by an uncaring industry.
"The Ramsays used to make films with new actors, so they were very happy to see me. And they took advantage of my face. It fit their movies easily. So I became a horror. My face was so scary; nobody could imagine me in any other role," he says.
"But I got kicked out by the industry after a point. So many people struggle so much. I got films, but they didn't always come frequently enough. I also needed a regular salary. I have no regrets, no anger or anything. I would have liked to act more, but it wasn't possible. I'm a public figure, lost somewhere in the background, in the crowd."
He isn't, quite.
Maybe there isn't an immense body of work to mark him out as one of the greats, but Agarwal certainly has his place in Indian movie history.
There has never been a better monster in this neck of the woods. In a different time, in a different industry, who knows how things would have worked out for him.
Shamya Dasgupta is a journalist, whose latest book Don't Disturb the Dead: The Story of the Ramsay Brothers has recently been published by HarperCollins India.