Here's my first try for an obfu. I came up with the little panel (based on a little-known regex tidbit) in the middle and went from there:

#!/usr/bin/perl
$cog = " %a3x+5o3*e4x2e4lx*+\nke4!";
$_ = '($_ = $cog) =~ my $a[4%5 +2*!3x/$scrunjaphmt + $] ];';

s[[];
m[]];
;cog;
eval;

print;
[download]

Hope you like it!