You're forming a closure on $thing, as well as returning a reference to it. voodoo() indeed!

One nice way to pretend you don't have a global variable when you do (I've talked about this one before):

{
    my $foo;
    sub foo () :lvalue { $foo }
}

foo = 'bar';
print foo, $/;
[download]

No sigil, that makes some people happy ;-)