package Factory;

sub fixup {
    no strict 'refs';
    my $pkg = 'Drone';
    *{"${pkg}::bar"} = sub { return $pkg; };
}

package main;

Factory::fixup();

@Drone::Subclass::ISA = 'Drone';
my $drone1 = bless({}, 'Drone');
my $drone2 = bless({}, 'Drone::Subclass');

print($drone1->bar(), $/);  # Prints Drone
print($drone2->bar(), $/);  # Prints Drone