Break Stack Exchange

Question

Trick the user that StackExchange is broken:

It can be done in several ways:

• Your program starts a browser in some certain way (with a proxy server, for example);
• Your program shows static picture;
• Your program is executed in address bar using javascript:.
• (your other creative way)

StackExchange error page should be displayed to user one way or another. It may appear immediately or after user tries to do something (i.e. to post a comment). The program should look like some useful StackExchange enhancer (e.g. a userscript that highlights happy posts, i.e. posts containing the word happy).

Try to aim for the shortest program (original tag was code-golf) and/or obfuscated code. You may depend on some concrete browser (Firefox, Chromium, Opera).

Encouraged:

• Preserving address line "normal";
• Finding actual faults in StackExchange software;
• Making it "hard to fix" (on this computer), e.g. making it cached;
• Making it show different error depending on on which site do I start the program (if it is a in-browser snippet);

Discouraged:

• Simply redirecting to http://.../error. You can still try to sneak it underhanded-style.
• Trying to permanently mess with user's StackExchange account.

(inspired by this)