I have two modules that use scalar objects:

package OnDestroy;

BEGIN {
   our @EXPORT = qw( on_destroy );
   require Exporter;
   *import = \&Exporter::import;
}

sub on_destroy(&) {
   my ($action) = @_;
   return bless(\$action);
}

sub cancel {
   my ($self) = @_;
   undef $$self;
}

sub DESTROY {
   my ($self) = @_;
   my $action = $$self;
   $action->() if $action;
}

1;
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and something I wrote in reponse to a question on PerlMonks:

package AutoExecute;

BEGIN {
   our @EXPORT = qw( auto_execute );
   require Exporter;
   *import = \&Exporter::import;
}

use overload
   '""'  => \&stringify,
   '&{}' => \&code_ref,
;

sub auto_execute(&) {
   my ($sub) = @_;
   return bless(\$sub); 
}

sub new {
   my ($class, $sub) = @_;
   return bless(\$sub, $class); 
}

sub stringify {
   my ($self) = @_;
   my $sub = $$self;
   return $sub->();
}

sub code_ref {
   my ($self) = @_;
   my $sub = $$self;
   return $sub;
}

1;
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All my other objects are based on arrays.