Yamcha is promoted into this position whenever he's onscreen whereas Krillin Takes a Level in Badass.Word of God states the main reason Krillin is a joke character is because Yamcha isn't around.
Snape from Potter Puppet Pals. If you need proof, look no further than this diary entry: "Today, the orange one accidentally drank one of my more expensive elixirs. He promptly vomited a glittering rainbow of foul waste, and the classroom erupted with applause, triggering my migraine. I aborted the class and was left to clean the boy's sick. Halfway through, Argus Filch showed up and bragged about his many affairs with Hogsmeade barmaids. Then he told me I smelled of broccoli and left without wishing me a happy birthday. Later, I noticed my bottle of sangria was gone. I settled for a cup of coffee, scalding my writing hand in the process and spilling it on my pants. I walked to the hospital wing, covering the wet spot with a book. Madame Pomfrey laughed and made me wait while she treated a student's runny nose. After an hour it became apparent that she had forgotten about me, so I returned to my room and found that I had locked myself out. I called for Filch, who turned up covered in lipstick and clearly having finished the sangria. He broke open my door, laughed at me, punched me in the shoulder too hard, and left me alone. I thought of my father."
Survival of the Fittest: Considering the setting, it's almost impressive that any one person could stand out above the rest as an example, but the world really just seems to exist entirely to make Jimmy Brennan miserable.
Chase of the CollegeHumor series "Troopers" seems to be shaping up as a Kenny-style Chew Toy, having already died more than once.
Evan Guido from Shiny Objects Videos is a minor example, though mostly he's just on the receiving end of Matt's tormenting.
A justified example in AJCO. Everyone loves to see Breyos suffer - even In-Universe - because he's that much of a Jerkass. He gets kicked around (sometimes literally) far more than any of the other Silo residents, and while he seems to be able to bounce back quickly with nothing more than a new layer of hatred for the world it's never very long before he starts to suffer again.
Joey from the Something Awful: Dungeons & DragonsLet's Play comes off as this. Early on, he's the first one to die (though he gets better). It's clear that, though he's ostensibly the leader, he's not particularly respected among his party, which he himself notes when they mock his poor rolls after he threatens to hit the next person who tries to split the party.
In several sprite videos on YouTube, Silver always gets injured in the most ridiculous ways.
Deacon from Video Games Awesome! manages to be both this and the series Butt-Monkey at the same time. People enjoy watching him be insulted by the other members of the show and frequently insult him as well, but he's usually the character who gets the most positive comments and love from the viewers as well.
Mario becomes this in Mario's Castle Calamity and the videos that have the same type of structure to it. Mario tries to destroy a castle, but fails numeros times as he and his friends (except for Toad, who Mario hates in these kinds of videos, and gets the same type of damage dealt to him), are beaten and battered in numerous ways, going from Mario getting his head sucked off by three squids stacked on eachother, to getting his face crushed by a Bullet Bill.
Pumpkinweenie from Phelous's Halloweenie skits always gets stabbed or humiliated by Halloweenie ever since he was introduced. To make matters worse for that pumpkin, Halloweenie was jealous during his "cancellation".
Harry Kim of Star Trek: Voyager, in SF Debris's reviews. "Poor Dumb Harry" endures a truckload of abuse from Parody Janeway, such as being demoted to a rank that doesn't exist, used as a footstool, beaten, dismembered, used as an experimental subject, beaten again, shot a few times and killed so often Janeway has to number the pieces to make him easier to put back together.