I had a vague inkling that fibonacci numbers were involved because of the ($i,$j)=($i+$j,$i) operation, and the comment that came with the code.

So, using Deparse:

$ perl -MO=Deparse obfu.pl
$" = '';
print "@{[&{sub {
    ($i, $j, @_) = (1, 1, split(//, 'hrP kc eeatenltarohsr u.J', 0));
    while (@_) {
        foreach $_ (1 .. $i) {
            @_ = (pop @_, @_);
        }
        push @t, shift @_;
        ($i, $j) = ($i + $j, $i);
    }
    @t;
}
;}];}\n";
obfu.pl syntax OK
[download]

That makes things a lot clearer. The @_ array is rotated fibo(n) times, and then the first element is shoved onto the end of @t.