Cypher leaps into action.
Imagine charging into a fight against people with powers such as unkillability, lightning bolts and earthquakes, and you've got ancient Greek. Such is the plight of Cypher, who is like the cruel punch line to the riddle, "Which of Zeus's powers would be the shittiest?" He can translate any language, but this power is "innate," meaning he can't understand or explain how -- so basically he's the Rain Man of the foreign language department, minus the gambling ability. In the comics, he functioned as a reverse Universal Translator. While the other mutants couldn't speak other languages, all the aliens and foreigners have always spoken perfect English until he turned up, and the writers needed to justify his existence.
Realizing they'd accidentally added "linguist" instead of "lasers," the writers behind Cypher started torturing the English language in ways even Cypher couldn't have justified to make him useful. He became a hacker because of programming languages, a master martial artist through body language and could even spot a building's structural weaknesses because architecture something something language. If they'd remembered that "language of love" was a phrase, he could have seduced Magneto into surrender, and that still wouldn't have been the gayest thing he'd done in a fight, since, for several issues, his combat strategy was to hide inside another X-Man -- the shape-shifting alien Warlock.
New Mutants #8
A relationship which accidentally invented Yaoi several years too early.
He was so useless that "feeling useless" became his character's story arc, which was even more annoying to read than cursive Cyrillic, and his lame powers made him do both while Wolverine was off-panel kicking ass.
It would actually have been less embarrassing if those were 80s shoulder pads.
Power: Biomechanical twin-maggot digestive system.
Maggott was a disaster of late 90s X-tremitude. His stomach was two biomech slugs which could eat anything and give him superstrength, but he was really conflicted about it and had unnecessary letters in his name. He was basically the lovechild of Matter Eater Lad and Spawn.
The worst superhero parents since Mr. and Mrs. Aquaman.
His powers turned him blue and caused him constant pain, because very-easy-to-draw graphical differences and complaining are the X-Men writers and illustrators secret strengths. He also has the worst career arc of any X-Man: He was dumped by the X-Men into Generation-X, immediately dropped by Generation-X after one issue into a concentration camp, and when you're dropped from a concentration camp it's because you're dead. Which happened, but wasn't the worst part. Being ditched by Generation-X is quickly more humiliating for mutants than exposition-triggered incontinence: One of their core characters' mutant power was molting, and another blew his own jaw off the first time he fired an energy blast.
Sorry, Maggott -- as you can see, we're well stocked with hero material.
Power: Six feet of extra-stretchy skin.
Reed Richards is a conflicted superhero because he's really smart but his power is really stupid. That is the only conflict Skin can resolve (by removing the smart part). His power is that he has six feet of extra-flappy skin he can control. If you noticed that skin should be measured in square feet because you'd need to measure its surface area, then well done on being smarter than the people paid to create new X-Men. He had the same powers as an ex-fat person, but without the dedication and self control required to earn it.
Uncanny X-Men #318
He also whined, but so did every X-Man with an X in their group name. Note how even his backpack has unnecessarily scrotal dangly flaps.
Skin isn't a combat organ. It's so weak against damage we invented armor. Hell, it's so weak against nothing at all we invented clothes. When your mutant power makes you more vulnerable to Indian rug burns, you really shouldn't be calling attention to yourself. Advice Skin didn't take. He was eventually crucified on the lawn of the X-Mansion, the wrong name was written on his gravestone and then he was dug up and cremated. That's writing someone out of continuity with extreme prejudice.
Excalibur #46 via Wikipedia
Power(s): Sound recording, catness.
Kylun could mimic any sound, directly causing an outbreak of voice-activated locks in terrorist forces worldwide. He also had magic swords which could not harm the pure of heart and looked like a lion, because Excalibur's creators were all seven-years old and Lion-O doesn't have lawyers. (Excalibur was the British X-Team, as you can tell by the way they having an extra letter in front of the "X" despite it being pronounced the same.) They were just smart enough to realize that mutant audio playback was a terrible idea, but not smart enough to be able to waste any idea they managed to have. The mess of random powers added on turned him into a cross between a Thundercat and a cassette deck, making him the second eightiest hero of all time.
He became increasingly feral as time went on just for something to do, despite that being the exact opposite of what happens when you hang around with people all the time. His one glorious moment came when a squad of "Warpies" assumed his sound-mimicking powers were no threat because they'd never seen Police Academy. His character was such an unemployable failure even in the X-community that his "happy ending" was finding and moving back in with his parents.
A more painful attempt to look cool than drinking liquid nitrogen.