They will all either be beautiful or humorous, but all will be obviously human.

9 seconds sound clip from the The Masque of the Red Death movie soundboard.

You can hear this line at 00:38:20 in the Blu-ray version of the movie.

Quote context

[...]

- The masquerade. I would devise something startling, novel, something that would be the talk of the entire revel.

- Have you told Prospero of this novel thing?

- I fear the Prince is much too austere.

- Will you tell me?

- Everyone will dress as usual. A harlequin, a Chinese, a soldier, or a princess.

- They will all either be beautiful or humorous, but all will be obviously human.

- I will come as a demon.

- Why not come as a great ape? When the guests are gathered, you would enter arms swinging, advancing toward the screaming lady with lowered head and grinning jaw.

- It'll be more than a costume. It will be a performance by the cleverest man at the court.

- Where would I get such a disguise?

- There is one in the room of stuffed animals.

[...]