Those are his magic words, you know.
4 seconds sound clip from the Fun and Fancy Free movie soundboard.
You can hear this line at 01:01:16 in the Blu-ray version of the movie.
Quote context
[...]
- Fe, fi, fo, fum he, hi, ho, hum.
- I'm the stuff, I'm tellin' you for here's what I can do.
- I can change myself into an elf, fly up high like the birdies.
- I can disappear into atmosphere... peekaboo. 'Cause I know the magic wordies
- Fi, fo, fe, foy fe, fe, fe, fe... Fifi? I don't know no Fifi.
- Those are his magic words, you know.
- Wait a minute now. He may be smarter than he looks.
- Oh, I hope he doesn't find them.
[...]