#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11137799
use warnings;

$_='ZBBBCZZ';

my @list = split ' ', s/(.)\K(?!\1)/ /gr;
use Data::Dump 'dd'; dd "given $_ got", \@list;

##</code><code>##

("given ZBBBCZZ got", ["Z", "BBB", "C", "ZZ"])