I was wondering what good is this spell. Seems to me like a modified variant of Mists of Releh. Maybe I'm reading it wrong.
Wrack reads:
Casting Modifier:-2
Sanity Cost:1
Any Phase: Cast and exhaust before making a Combat check. This combat immediately ends as though you had succeded at an evade check.
Mists of Releh reads:
Casting modifer: special
Sanity Cost:0
Any Phase: Cast and exhaust to pass an evade check. The casting modifier is equal to the monster's awareness
So from what I understand, Wrack was introduced to better deal with monsters who have Ambush and high awareness? Seems really limited to me.