This seems to do what I think you want using your data.

use strict;
use warnings;

my @strings = (
   q{asdfgGOATaewrjgn},
   q{ererGOAskjgbrTslkgjnjng},
   q{ccG<!-- comment on status of global geopolitical economics -->OAj
+gTsvs},
   q{aGO<h3>i hate clowns</h3>ATbbb});

my $needle    = q{GOAT};
my @parts     = split m{}, $needle;
my $notNeedle = qq{[^$needle]*};

my $haystackPatt = q{(} . join($notNeedle, @parts) . q{)};
my $rxHaystack   = qr{$haystackPatt};

my $stuff1 = q{^^^};
my $stuff2 = q{+++};

foreach my $string ( @strings )
{
    print qq{$string\n};
    $string =~ s{$rxHaystack}{$stuff1$1$stuff2};
    print qq{$string\n\n};
}

[download]

It produced this output.

asdfgGOATaewrjgn
asdfg^^^GOAT+++aewrjgn

ererGOAskjgbrTslkgjnjng
erer^^^GOAskjgbrT+++slkgjnjng

ccG<!-- comment on status of global geopolitical economics -->OAjgTsvs
cc^^^G<!-- comment on status of global geopolitical economics -->OAjgT
++++svs

aGO<h3>i hate clowns</h3>ATbbb
a^^^GO<h3>i hate clowns</h3>AT+++bbb

[download]

I hope this is useful.

Cheers,

JohnGG

Update: Fixed typos

Update 2: Changed initialisation of $notNeedle so string was not hard coded, original line was my $notNeedle = q{[^GOAT]*};

In reply to Re: More Regexp Confusion by johngg
in thread More Regexp Confusion by mdunnbass

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.