regular expression/comments issues

[c0ncrete]

i just ran into a really weird problem that i can't seem to sort out and i was wondering if someone could take a look at it and tell me if i'm doing something obviously wrong.

the following script works as expected. all of the patterns that i have stored as scalars are matching correctly.

use strict;
use warnings;

my $kobolds = '^#(broken|over|pox|s(elan|l(a|i)ve|pider)|the)|(a_)?glooming';
my $spiders = '^#venom|a_gloom(_|f)';
my $rats    = '^#r(at|uf)|a_(cave|diseased)_r';

my @kobold_list = (
    '#Brokenclaw',
    '#Overlord Gnikan',
    '#Pox',
    '#Selandoor',
    '#Slavemaster Ruga',
    '#Sliver',
    '#Spider_Tamer_Gugan',
    '#The_Gloomingdeep_Locksmith',
    'a_garroted_kobold',
    'a_Gloomingdeep_captain',
    'a_Gloomingdeep_grunt',
    'a_Gloomingdeep_plaguebearer',
    'a_Gloomingdeep_slave_warden',
    'a_Gloomingdeep_spiritweaver',
    'a_Gloomingdeep_warrior',
    'Gloomingdeep_Spiritweaver',
    'Gloomingdeep_Taskmaster',
    'a_kobold_barrel'
);

foreach my $npc (@kobold_list) {
    if ( $npc =~ m/$kobolds/i ) {
        print "MATCHED: $npc\n";
    }
    else {
        print "NOT MATCHED: $npc\n";
    }
}

print "\n";

my @spider_list = (
    '#Queen_Gloomfang',
    '#Venomfang',
    'a_gloom_spider',
    'a_gloom_spiderling',
    'a_gloomfang_luker',
    'a_small_spider'
);

foreach my $npc (@spider_list) {
    if ( $npc =~ m/$spiders/i ) {
        print "MATCHED: $npc\n";
    }
    else {
        print "NOT MATCHED: $npc\n";
    }
}

print "\n";

my @rat_list = (
    '#Ratasaurus',
    '#Rufus',
    'a_cave_rat',
    'a_diseased_rat',
    'a_small_rat'
);

print "\n";

foreach my $npc (@rat_list) {
    if ( $npc =~ m/$rats/i ) {
        print "MATCHED: $npc\n";
    }
    else {
        print "NOT MATCHED: $npc\n";
    }
}

running it results in the following output:
(for some reason an extra newline is printed after the final $npc in @spider_list)

C:\EQEmu\sandbox>perl test_matches.pl
MATCHED: #Brokenclaw
MATCHED: #Overlord Gnikan
MATCHED: #Pox
MATCHED: #Selandoor
MATCHED: #Slavemaster Ruga
MATCHED: #Sliver
MATCHED: #Spider_Tamer_Gugan
MATCHED: #The_Gloomingdeep_Locksmith
NOT MATCHED: a_garroted_kobold
MATCHED: a_Gloomingdeep_captain
MATCHED: a_Gloomingdeep_grunt
MATCHED: a_Gloomingdeep_plaguebearer
MATCHED: a_Gloomingdeep_slave_warden
MATCHED: a_Gloomingdeep_spiritweaver
MATCHED: a_Gloomingdeep_warrior
MATCHED: Gloomingdeep_Spiritweaver
MATCHED: Gloomingdeep_Taskmaster
NOT MATCHED: a_kobold_barrel

NOT MATCHED: #Queen_Gloomfang
MATCHED: #Venomfang
MATCHED: a_gloom_spider
MATCHED: a_gloom_spiderling
MATCHED: a_gloomfang_luker
NOT MATCHED: a_small_spider


MATCHED: #Ratasaurus
MATCHED: #Rufus
MATCHED: a_cave_rat
MATCHED: a_diseased_rat
NOT MATCHED: a_small_rat

the moment i add a comment anywhere in the script, nothing beneath that line will execute. i've tried escaping the # symbols in the patterns and everything else i could possibly think of, all to no avail.

i'm at a loss here... any ideas?