Just in case you really are trying to make a serious point...

From his posts it's clear that the OP meant scary in the literal, rather than wacky and ironic, sense.

Actual songs are only ever used in celebration or for light relief - 'scary' isn't even close to being a factor.

But there are certainly plenty of scary score cues. I think the creepiest is the one that accompanies Boushh/Leia's sneaking around Jabba's palace and reawakening Han. The tension doesn't break until the helmet comes off ;-)