Green’s Dictionary of Slang

(US black) a dancer.

1926		Van Vechten Nigger Heaven 281: ’Toly, you sho’ is one bardacious scroncher. You’s goin’ git scronched.
1931		N. Van Patten ‘Vocab. of the Amer. Negro’ in AS VII:1 30: scroncher. V. n. Dancer.