Galz had extra scary and cache. He put extra scary on top. I herp derped and put extra scary on cache. What should have happened was extra ascary flipped until it got a monster which would have been behemoth but Galz had reordered those too because we treated it as extra scary cache.
In short cache didn't happen your facing an extra scary behemoth
This isn't how it works either. I don't need you to fix it or anything, just telling you how it works.
I use Wand to leave Extra Scary followed by Cache on top. We reveal Extra Scary. It's not an encounter, so we keep going (same turn). Cache. It is an encounter, but Extra Scary doesn't modify it. Cache happens.
Next turn. I use Wand again on two new cards. Let's suppose the first one is a Slime Monster. Okay. So it's an Extra Scary Slime Monster.
Wand only works at the start of a turn - it doesn't get a chance to do anything in-between Extra Scary and the next card. Extra Scary modifies the next monster - that's what it does when you turn it over, and it can wait multiple turns until there finally is one to modify.