That is the scientific explanation. But, no doubt, you people would prefer a more colourful one.
6 seconds sound clip from the Dead of Night (1945) movie soundboard.
You can hear this line at 01:36:38.067 in the Blu-ray version of the movie.
Quote context
[...]
- Why, hello, Sylvester. I've been waiting for you.
- You mean that half the time Frere was Frere and the other half he was his dummy?
- Exactly.
- And in the end, the dummy got the upper hand entirely.
- Yes, but how did the dummy get from one room to another? Under its own steam?
- That is the scientific explanation. But, no doubt, you people would prefer a more colourful one.
- That Hugo had become endowed with an existence of his own.
- Drink? Oh, I'm awfully sorry.
- Blimey, George is dying on us.
- There's nothing to be afraid of. We're your friends.
- None of you can help me. I must be left alone with Dr. Van Straaten. Please.
[...]

 Dead of Night (1945)
 Dead of Night (1945)  Phantom of the Opera (1943)
 Phantom of the Opera (1943)  Scooby-Doo, Where Are You! (1969)
 Scooby-Doo, Where Are You! (1969)  Halloween III: Season of the Witch (1982)
 Halloween III: Season of the Witch (1982)  Knight Rider (1982)
 Knight Rider (1982)