Rubbish.

#!/usr/bin/perl

use strict;
use warnings;

my $loop_line = "static replace [something] and [another] thing";

my @matches = $loop_line =~/\[(.*)\]/; # Build a list of matches
for ( @matches ) {
    $loop_line =~ s/\Q$_\E/PING/;
}

print $loop_line, "\n";

__END__
static replace [PING] thing
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The problem with the given code is the use of .*, which your solution doesn't solve at all. In fact, your solution doesn't address any problem. It's just adding slowness. It's worse than not giving an answer.

Abigail