The goal should not be to terrify the bejesus out of the public, lest they scrunch their noses and give up.
1825, "to bite," intensive form of crunch (v.); ultimately imitative. Meaning "to squeeze" is recorded from 1835 (implied in scrunched). Related: Scrunching.
[ultimately fr late 16th-century scruze, ''squeeze,'' perhaps a blend of screw and squeeze]