Veronica Lodge. Being the Spoiled BratRich Bitch that she is, don't even suggest that her cooking is anything less than superb. In one comic, Veronica was preparing what Archie called "rainbow cookies". Since they looked like ordinary cookies, Mr. Lodge asked what he meant by that. Archie responded with "Sometimes they make you turn blue, sometimes they make you turn red, sometimes they make you turn green..." Later in the comic, the president of a food company tried her cookies, and the result prompted Archie to say, "Purple? Never seen that color before!"
Another comic shows Reggie eating some dinner Ronnie's cooked for him, but he finds it inedible; so he dumps the whole plateful into the dog's dish, then tells Ronnie that the food was superb. A moment later, the dog sniffs at the food in his dish—and picks up his dish with one paw and empties the whole lot back into Reggie's plate.
Ms. Beazly, the lunch lady. Students who eat from the high school caf0 are inevitably shown later doubled over in poisoned agony. One case of stomach cramps she was blamed for, though, was actually the result of some stickers popular around the Riverdale High students; their glue was toxic enough to cause them. When Archie with Professor Flutesnoot's help proves this one time she was innocent Mr. Weatherbee is quick to reinstate her—and Ms. Beazly gives Archie a gourmet-level meal in thanks for a chage.
Olive from The Beano (she's a "School Dinner-lady", who is a Lethal Chef subtype of her own). Her "Tea" was actually a highly-reactive acid-like corrosive; her oxtail soup moos and flicks its tail; the skin on her custard couldn't be broken with a pickaxe, and so on.
In one particularly badly-written issue, Alfred took skill levels in lethal chef. He ran out of baking soda, so he used salt instead.
The Robins from Li'l Gotham arn't much better, if their attempt to cook for Alfred was any indication.
Moira MacTaggert and her coffee. If there was a complaint desk in Excalibur's Muir Island base, probably this would be on the top. To the extent that when Kitty volunteered to take Pete Wisdom to London to check on a friend of his, Brian told him "Buy some coffee while you're there! We've run out of Rory's good stuff." And it didn't even escape Xavier's notice. He once quipped that Jubilee was using Moira's coffee to lubricate her roller skates, and also remarked on it during a video-phone call with Moira:
Moira: Och, it's noon and I'm still barely up. It's the break o' dawn wi' you and ye look fresh as a daisy. Ye make me sick, Charles Xavier.
Professor X: No, Moira. It's your coffee that makes you sick.
Paige has been shown to be able to cause boiling pasta to burst into flames. Pasta that is submerged in water.
(while discussing Survivor's food challenges) Peter: That reminds me. I think Mom is letting Paige cook dinner tonight. Jason: A perfect example. Have them eat something like that! Peter: But don't you need to have a survivor?
Roger is also shown to be this, when he's grilling hamburgers or on the rare occasions when Andy's out and he's left to cook for the kids.
Andy is the most frequent victim of this trope in the comics. While she's capable of making perfectly edible food, because she's a health nut Andy usually makes meals out of tofu, Lima beans, and whatever other sort of "healthy" foods that frequently make her family sick and they hate the taste of even if it doesn't. Her family constantly complains about her cooking and attempts to sabotage it, but she's either oblivious or doesn't care. One of the reasons Andy hates her own mother is because she's the direct opposite.
Irma's diner has notoriously bad food. The soup has hair in it with rollers, the coffee tastes like turpentine, there is a hoof in the meat loaf, the cows for the hamburgers are burned alive, and so on.
"Cookie", the military cook from Beetle Bailey has a knack for bad cooking (a common stereotype of military cooks). Jokes about his meatballs are the most common. Thankfully, one of the soldiers he caters to is Sargent Snorkel, who will eat anything.
Yosefa from the Israeli comic Zbeng! specializes in inedible, rock hard doughnuts. She once used a batch of radioactive yeast to make them extra fluffy, which created a gigantic mutant doughnut that threatened to crush the school.
And even worse, she has a truly loving boyfriend, who eats everything she cooks. He is a model patient in the hospital's stomach pumping section...
Calvin and Hobbes: Calvin is a bona fide Lethal Chef. In one strip, Calvin's Mom is sick so Calvin makes her breakfast in bed: orange juice, eggs and toast. Calvin delivers his mom the eggs smoldering and with a chisel to chip it out of the pan. When his mom asks about the orange juice and toast, Calvin replies "Dad said not to tell you about that until you're better".
Calvin's mom herself could certainly qualify as well. Though Calvin is prone to gross exaggeration on how bad her food is (just as he is with everything else), there isn't much that goes on the family's dinner table that is visually identifiable as food. Most dinner plates are filled with what can only be described as "glop", which sometimes takes on colors that no food should ever be. Even Calvin's dad sometimes comments on this:
Dad: I thought we were having stuffed peppers. Honey, what the heck IS this? Whatever it is, I'm not eating it!Context Mom got Calvin to eat by telling him they were monkey brains. Calvin talking about monkey brains at the dinner table is what gets this reaction from Dad.
He not only tries to mix fish and strawberries with cream and alcohol, he actually manages to make a living sauce, which escapes its bowl to crawl around...
He also invented the "horror kitchen".
And almost assassinated the president with a flambéd crêpe. Apparently, he was using rocket fuel as the flambéing reagent.
Hägar the Horrible's daughter, Honi, is such a horrible cook she even manages to mess up cooking water.
In Bone, Gran'ma Ben/Rose's teacher tries to put stinky cheese on Smiley's quiche and serves up some disgusting green stew that practically everyone despises. Bartleby, on the other hand, loves it.
The Cook from Sturmtruppen. His spaghetti is known for strangling soldiers and he once turned the lunch in a living monster. When the Sergeant added motor oil to his soup, nobody noticed the difference until a motorist asked for his oil can back.
Monica from Brazilian comic Monica's Gang is prone to cooking awful things such as gumbo flan, yogurt pizza, or a "health juice◊"note in case you're wondering, the characters become dinosaurs because of a serum that fell on the juice, not the juice itself.
Two examples from the comic book version of W.I.T.C.H.:
Will's attempts at cooking includes things like baking with powdered soap in place of flour.
Orube, an alien friend who, when first arrived on Earth, mistook money for food (she complained it didn't taste well) and has apparently set on fire the kitchen the first time she tried to cook. Differently from Will, it's more about lack of familiarity with Earth cooking implements and ingredients (in a later special it's confirmed she never set the kitchen on fire again) and clumsiness when trying to cook for other people (she destroyed the water tap in her kitchen while preparing pasta due being in a hurry), even if she still has a long way to go (in that special she managed to burn the pasta).
Egon, the Foreign Legion chef in Beau Peep, veers between this and Cordon Bleugh Chef, but is mostly this. Peep once ate the contents of an ashtray and thought it was only marginally worse than normal.
Granny from Popeye has somehow managed to burn water and her biscuits have been used to pave driveways. Her cooking is so bad, Popeye, Poopdeck Pappy and Swee'pea only allow her to cook one meal a year, and on that day, they usually sneak out to Roughhouse for a hamburger.