Blob
This mutant's main virtue from the Marvel Universe is to be morbidly obese! Because of it, he is capable of absorbing bullets or stopping them without him being harmed and creating a kind of gravity field around him. On the other hand, his health and movility are pretty limited.
Color Kid
This character's only ability is to be able to change the color of stuff. He has the habit of switching the sky's color with that of the ground, to confuse his adversaries. Really, who would be dumb enough to let himself be defeated by a COLOR confusion of this kind?
Tag
This unkown hero's only superhero, a mutant from the Marvel Comics, is to force people to run. Sure, this can come in handy when you want to scare of the villains, but how could it be usefull to defeat them and prevent them from doing their misdeed somewhere else?
Bouncing Boy
He's capable of inflating like a balloon and to fly in the air. According to his story, he aquired this "superpower" after drinking some kind of plastic formula that kinda looked like a soda pop. The most ridiculous thing from this character is that he has to roll or fly away from his enemies.
Cypher
One of the mutants from the lastest Marvel Comics generation, his hability is to understand absolutely every language in existance, both in oral as well as written form. Unlike almost every other superpower, this would be extremely helpfull in real life, but on the comics that is not the case. How could you use the knowledge of every language in existence to attack and defeat an enemy?
Matter Eater Lad
This guy has the capacity of eating anything, including rocks. His superpower would also be sort of usefull in the real world, and could even end hunger and nutrition problems around the world, not to mention the complaints of eating so much meat; but on the comic world, it is extremely useless.
Zan, from the Wonder Twins
His hability is to be able to transform into any type of body water at will. For example, he can transform himself into ice sculptures and he can wet beds. What's more, his powers are useless unless he previously activates them by hitting a Power Ring he has with another one that his twin sister, Jayna, has.