#The regex, commented for your convinence.
$Error =~ /Sequence\s #opening anchor, don't capture
              ( # open capturing group to get target pattern
                 .+? # target pattern, non-greedy catch all
              ) # close group
              \sconsists # closing anchor, don't capture
          /x; # end regex

##</code><code>##

($Missing_Living_Being) = $Error =~ /Sequence\s(.+?)consists/;