The shittiest project I ever worked on was a php project that was converted from another language (I don't remember which one). This doesn't sound bad, except they used software to automatically convert it. The PHP code had no comments, minimal white space, and the variables were all hex. My job was to fix bugs. I worked there for about a week before I quit in frustration.
It was the result of automatically porting a codebase written with a RAD system called Gupta Team Developer / SQLWindows[1]. The original language supported multiple inheritance and the converted code was a huge mess of tangled interfaces trying to reproduce that. The tool generated lots of duplicated code and some monster constructs like a static class with 140.000 lines of code, with all public methods.
I still weep for my colleagues who were left to tame that mess.