A segment of perl code (usually a regex of some sort, sometimes not) that looks all for the work like the extended ascii symbols you get in your term program when you wiggle the phone plug. Happy lines like:

~ /(^\d{5}$)|(^\d{9}$)/;
...that could be confused for 31337 hax0r talk, or typical Wall-esque hillarity like
@a=(Lbzjoftt,Inqbujfodf, Hvcsjt); $b="Lbssz Wbmm" ;$b =~ y/b-z/a-z/ ; $c = " Tif ". @a ." hsfbu wj" ."suvft pg b qsphsbnnfs" . ":\n";$c =~y/b-y/a-z/; print"\n\n$c ";for($i=0; $i<@a; $i++) { $a[$i] =~ y/b-y/a-z/;if($a[$i]eq$a [-1]){print"and $a[$i]." ;}else{ print"$a[i], "; }}print"\n\t\t--$b\n\n";
...that will give you permenent headaches. It is code that only makes sense if you know what it's output is supposed to be. Not always obfuscated, sometimes just more efficient.

Naw, I'm kidding. It's always Obfuscated. Proof that Perl = Line Noise.