I suspect there are owls in the bog (jag anar ugglor i mossen) means something is really fishy or suspicious.
Now you have really shit in the blue cupboard (nu har du verkligen skitit i det blå skåpet) means that you have done something that's so far out of line or with such dire consequences that there is no return away from this. Kinda like a harder way of saying "now you've done it".
To throw water on a goose (Slå vatten på en gås) means to say something that won't be comprehended or taken seriously by the recipient at all, either because of stupidity or because they are too locked in their mindset.
Also the Swedish classic "glida in på en räkmacka" ((to) slide in on a shrimp sandwich), which basically means to end up somewhere (location, career, situation) without any difficulties. The shrimp sandwich symbolizes a life without difficulties or in some luxury.
Then there's also "halka in på ett bananskal" ((to) slip in on a banana peel), which is similar to the above, but not always favorable and you don't have any plan or preparation. You just winged it or it just happened by accident.