It's midareyo or midareyou, one word. Midare yo doesn't make sense.
It's been translated as "wreck havoc" and "break havoc", which are not good English. The phrase is "wreak havoc".
I don't think "wreak havoc" is a good translation anyway. Dictionaries give things like "be out of order" and "lose control"; it's an intransitive verb that refers to something that happens to you, not something you inflict. (The transitive version is midasu "disturb".)
At the very least, the tag boku_to_midare_yo? needs to be corrected to boku_to_midareyo?. But I don't think using a specific phrase as the basis of the tag is a good idea, since the same pun is made with different forms: the game itself has midaretai no, midaretainda ne, midarechau yo and midarechao; post #1948605 has Kashuu Kiyomitsu saying midasareteru yo, etc. I'm not sure what to call it.