The worst web comic ever is, in my opinion, Angel Warrior Comics by Martin 'Hiro' Jackson.
Description: It's a sprite comic.
Good: All the links work, I guess.
Bad: It's the worst web comic I've ever read.
I'm serious. I've never seen a worse comic. I don't mean this in a fun way, or a jokey, ironic way. It is truly painful to read. Agonising. Awful. Interminable.
The author (despite being aged 17, apparently) has never even HEARD of full stops. EVERY sentence in the entire comic (seriously) ends with an ellipsis, an exclamation mark, a question mark, or nothing at all. Many sentences run on for ever, separated by commas. This alone is enough to doom the comic. It makes reading the dialogue pure agony for anyone with the remotest grasp of English.
Capitalisation? Optional. Storyline? Nope. Utter randomness. Random rubbish. I would guess that lack of plot for the first part means that it's actually meant to be a gag comic, but I honestly can't tell if there are any jokes in there. The only time it genuinely made me laugh was about comic #100. The author pops up and says words to the effect that "It has come to my attention that this comic is starting to suck." I snorted with laughter at that point. It ALL sucks. Right from strip #1.
The lettering is too small to read without screwing your eyes up and going nose-to-nose with your monitor. The artwork is, as previously indicated, mostly Megaman sprites - poorly recoloured Megaman sprites, drawn from what is clearly a very limited selection. (He even has the nerve to offer a three-part tutorial on recolouring them. Just recolouring. Not creating new poses, not inventing new characters... just recolouring.) The website itself is done up in eye-gouging bright green on bright blue... oh, it's all miserable.
I strongly advise against even bothering to read this. You're wasting your time. I doubt you'll get past the first comic before closing the window in in a fit of despair.
Overall: A symbol of everything that is wrong with the webcomic world. Genuinely the worst comic I have ever read. Zero out of ten.