The others have already pointed out why that's not a good idea. But to show it's still possible, I assume the following is close to what you want:

package Bar;
use strict;

use Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(the_mascot);

my $value = "camel";
my $data = \$value;

sub the_mascot {

print<<"END";
Hey, did you know that Perl's mascot is a:

$$data

END
}

sub new {
    my $class = shift;
        my $self = {};
        $self->{ANIMAL} = $data;
        bless($self, $class);
        return $self;
}
 
sub animal {
    my $self = shift;
    ${$self->{ANIMAL}} = $_[0];
}

sub mascot {
         the_mascot();
}

1;
[download]

Then in main script:

use strict;
use Bar qw(the_mascot);

my $a = new Bar;
$a->animal("parrot");
$a->mascot;

the_mascot();

$a->animal("firebird");
$a->mascot();

#output
__END__
Hey, did you know that Perl's mascot is a:

parrot

Hey, did you know that Perl's mascot is a:

parrot

Hey, did you know that Perl's mascot is a:

firebird
[download]

</code>