User blog comment:Wintermelon43/any cool things you know that you can do on your userpage to shock people?/@comment-10350197-20130814220326/@comment-5691231-20130814222605

Hey! To edit the background on your profile, you'd have to edit your sup.css.

As for the message wall greeting, you can edit this at Message_Wall_Greeting:SOMEGUY123.

For the autoplay music incase - you'd have to install the coding for this via MediaWiki pages on your Wiki, with additional templates to run it.