use strict;

package Object;

sub new {
  bless {}, "Object"
}

sub foo { "ObjectFoo\n" }

package Tied;

sub TIESCALAR {
    my $class = shift;
    my $o = shift;
    bless \$o, $class;
}

sub FETCH {
    my $self = shift;
    print "<fetch>\n";
    $self
}

sub foo { "TiedFoo\n" }

package main;

my $o = new Object();
print $o->foo();

tie $o, 'Tied';
print $o->foo();

untie $o;
eval { print $o->foo() };
print "NoFoo\n" if $@;