This leaks one object every time you hit return, then tells you how many scalars there are. (The memory leaks because $bar has a reference to itself, and so its reference count will never reach 0.)

#! /usr/bin/perl -w
use strict;
use warnings;
use Devel::Leak;

while(1) {
  my $count = Devel::Leak::NoteSV(my $foo);
  print "$count";
  <>;
  my $bar;
  $bar = \$bar;
}
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