Trying to find anything good about you is like trying to shove butter up a porcupine’s ass with a red hot poker.
(only applicable when insulting women)
(warning, it’s crude)
I’m going to kick you in the cunt so hard that I’ll wear you like a snowshoe
No insult I could give you could surpass the one Nature gave you first.
You’re so fat, when you bust through the wall people yell “Hey, Kool-Aid!!”
I heard you once butled a monkey. And liked it.
If you and my ass were in a beauty contest, the crowds would jump to their feet and shout “Hooray for the one-eyed man!”
You are a cheap, lying, no-good, rotten, four-flushing, low-life, snake-licking, dirt-eating, inbred, overstuffed, ignorant, blood-sucking, dog-kissing, brainless, dckless, hopeless, heartless, fat-ass, bug-eyed, stiff-legged, spotty-lipped, worm-headed sack of monkey sht.
(Thank you, Clark Griswold ;))
I wonder what you would be like if you had gotten enough oxygen at birth.
And the winner…
You live in Georgia…that’s insult enough
I think you need to get your neuromuscular junctions checked out, just incase they don’t exist.
egg
watch it ultress. Besides, red clay mud is a lot easier than tar to wash off one’s heels. 
Mullinator you’re so ugly, your mother had to tie a pork chop around your neck to get the dog to play with you. How’d you get that huge wart on your neck…oh wait…that’s your face.
(APOLOGY in advance - I ripped this insult off of someone’s sig line here, and I’ve been using it RAMPANTLY ever since. I would gladly credit them if I could remember who they are, and I wouldn’t normally re-post something like that, except it’s soooo perfect for this thread. So, whoever it was, I pay homage to you by posting the following insult)
**
You couldn’t find your ass with both hands, a map, a compass, ass-finding radar, and “The Complete Idiots Guide to Finding Your Own Ass”!
**
And this is the best you people can do? I ask for creative insults and a chance to clear the dreariness that rots in your minds from you banal existence, and all I get are some half-hearted, limp attempts to send a warning shot across the bow of my ego.
Metalhead - you’re so unoriginal. 
Of course, I ripped it from a post made by Legomancer, so I’m just as derivative. 
Hey, Mully, what do you do on Father’s Day? Send a card to all fourteen suspects?
Hey, Mully, I heard you visited the zoo and they made you show ID on the way out.
Hey, Mully, if I had a dollar for everytime you did something right, I’d have to get a second job to get out of debt.
Hey, Mully, is it true that whenever you lay down at the beach, stray cats scratch sand at you?
Hey, Mully, I heard you’re so bad with the ladies, you get rejected by 900 numbers.
Hey, Mully, you’re so ignorant, Cecil Adams is waving a white flag.
This has to be done. Can’t be helped.
<massive guybrush threepwood hijack>
You fight like a dairy farmer.
Soon you’ll be wearing my sword like a shish-kebob.
I once owned a dog that was smarter than you.
This is the END for you, you gutter-crawling cur!
You’re no match for my brains, you poor fool.
You make me want to puke.
You have the manners of a beggar.
There are no words for how disgusting you are.
Have you stopped wearing diapers yet?
I’ve spoken with apes more polite than you
etc.etc.etc.
</massive guybrush threepwood hijack>
Mullinator has tremendous self-esteem…for no apparent reason.
Yeah? Well, your momma’s boots have instructions written on the heel!
You do a pretty good Spongebob Squarepants, for what that’s worth.
Every male armadillo in Texas has your momma’s phone number.
Two. Two boxes of rocks.
He’s alive because bullets cost twenty-five cents each.
What? You’re still alive? Five guys and two gals want to snuff you for free!
[Homer Simpson]
You couldn’t fool your mother on the foolingest day of your life if you had an electrified fooling machine.
[/Homer Simpson]
Darwin wrote your obituary.
And it needs to be said.
You, Mullinator, are so vain you’d even start a thread asking people to creatively insult you just to get attention.