There must have been some magic in that old silk hat they found, for when they placed it on his head he began to dance around.
15 seconds sound clip from the Rudolph and Frosty: Christmas in July movie soundboard.
You can hear this line at 01:17:19 in the Blu-ray version of the movie.
Quote context
[...]
- He does have something. I dunno. He might have something. Why not ask the genie?
- Frosty the Snowman has his own magic which could prove quite valuable.
- Really? Tell me, what is it?
- His hat.
- Why, you could bring an army of snowmen to life.
- And Frosty, the only one who knows the true secret of Rudolph's nose, would be lifeless.
- But what could I give Frosty for his hat?
[...]