Not sure if this helps but it is a good place to start

ecarroll@x60s:~/code/perl/obfu$ perl -MO=Deparse ./test
($;, $_, $|, $\) = ("Yoo*se\177*cd*Mcpk+", ' ' x 17, 1, "\r");
{
    vec($_, 1 + $", $^F << $^F) = ord($/ ^ substr($;, $" = int rand 16
+, 1));
    select $,, $,, $,, $| / ($| + tr/ /\000-\037!-\377/c) if print $_;
    redo if tr/ // > $^F ** 2;
}
[download]

I think you're also going to want to perldoc all those variables (that he isn't getting in the first statement) for their defaults. I don't think he is doing anything (too) special with them. Some of it is easily reduced.