The biggest, reducable Python code I could think of that prints "HELLOWORLD".
I made this as challenge to myself after seeing those obfuscated code contests, and I thought of doing the same myself. I wouldn't say this is very obfuscated (in fact I have to leave some numbers and strings, because I don't know how to obfuscate them), it's obfuscated enough to be unreadable (for humans, at least 😉)
I might going to give the information of how this monster works.