The other day my friend was complaining about salt bagels, asking why they exist, and I said "So deer can lick their wounds." I love making new, barely-sensical idioms - they only appear to make sense if not read too deeply, but most everyone who hears them understands where the phrase is coming from/what it is referencing."Don't look a gift horse in the two bushes"
I have two for you. 1 from tonight: "Sounds like a rock star!" Comes from kind of combining "Sounds good" and "You're a rockstar." Like, "I totally approve of all of these things [that you are doing]!" I mean, rock stars, by definition, sound good, so I feel like this is an easy one. 2 just remembered this one I made up on the spot sucks more balls than a vacuum in a cotton factory