I thought it was called The Frog. The story was about a man (I always look back and think it was a reporter) who came to this mansion. It was owned a family dynasty and the business was created by the original ancestor and passed down only to the family.
When the man got to the mansion, he was told there was no interview with this tycoon but for some reason he was stuck there. So, he was told he could move around but not to go upstairs and every night his door would be locked until dawn.
The head of the business was very intelligent and had not married. He conducted all his business on the phone but never went to the company in person. Everyone who worked there catered to him and took care of his every need. And really seemed to care about him. But he never went out in public. However, at night, he came down the stairs and went out to the swimming pool, which was in the middle of a maze, and swam all night.
The viewer could only listen to the same sounds the man did. It was kind of "slurp, bump, drag, slurp, bump, drag…" and it sounded wet, which in those days was creepy because you had to use your imagination.
The man got out one night just as the mogul was going up the stairs and he saw, yes, a giant frog. When the mogul realized the man was there, he/it started screaming and panicked and tried to hurry up the stairs. The staff threw a blanket over him.
Unable to live like this any more and not wanting to have children, he jumped (no pun intended) out the window and committed suicide.
The man was told that, although the frog could speak and think like the human his brain was, every generation had a male born looking like a frog. It was something genetic in their DNA. This man was sick of living like this and afraid of passing on the DNA. He was the last living person in the family. And being seen for what he really looked like was the final straw and he felt he needed to end it.
It was in B&W and was from, I think, the 30s or 40s. I saw it twice. Once sometime during the 60s and then in the early 70s on a Saturday weekly horror show. It was not gory or anything and no one saw it until the end. I am almost 80 and back in those days, we found terror in things like sounds or the unknown. No gore, nudity, slashing, etc. This movie was scary but I love it. In the end, after seeing the big frog and hearing the story, I felt sorry for the guy and his family and all the people who had cared for them.
For those who have mentioned the X-Files, there was an episode about incest/DNA and was so horrid it wasn't shown in reruns or syndication. I don't know if it was included in the box set. So, maybe the idea did come from this movie.
I don't remember all the people being in it, like the trailer for The Maze (which could be a remake because people thought it was pretty tame, as time passed, but a good idea for a movie).
I have looked for this movie over the years and never found it. If anyone finds it for sale online, please let me know.
However, since this was posted in 2018 and it is now 2024, I don't think anyone will read this and whoever posted it probably isn't even a member any more. LOL Just glad to know that there are people who saw the same movie I did, over the years.