A sample of creating a dangling (unfreeable) reference and retrieving a stringified reference. Don't try this at home.

use 5.008001;
use B;
$z = [0..9];
use Devel::Peek "SvREFCNT_inc";
$foo{0+$z} = 1;
$z = \\@$z;
SvREFCNT_inc($$z);
undef $z;
$key = each %foo;
$obj = bless \$key, "B::AV";
print @{$obj->object_2svref};
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