use strict;
use warnings;
use 5.010;

my %h = qw{a 1 b 2};
my @h = (100, 200, 300);
my $h = 10;

*all = \%h;
*all = \@h;
*all = \$h;  #<overwriting that strange variable??>

say ${*all}{a};
say ${*all}[0];
say ${*all};

--output:--
1
100
10