There have been many attempts to make a Fantastic Four cartoon work, but none of them have panned out. The 1978 version stands out as particularly egregious, as it doesn't even have most as it didn't even feature the four original members. Instead of the Human Torch, we got H.E.R.B.I.E. The endlessly punchable robot was essentially a combination of Jar-Jar Binks, Scrappy Doo and those racist robots from Transformers 2, voiced by what sounds like a meth-addled Marvin the Martian.
The program has the Marvel Super Heroes problem of barely qualifying as animation. It might have more moving parts than that old relic, but it lacks the Jack Kirby art for a basis. As a result, the show has a distinctly sub-Jabberjaw level of visual quality.
While the cartoon did include classic FF villains like Dr Doom and the Mole Man, their most memorable exploit was their laughable run-in with Magneto. Reed Richards broke down the X-Men villain by simply pointing a wooden gun at him.
Mags was so depressed at his own stupidity that he willingly surrendered to the police and entered the back of their clearly metal police car.
But that's nothing compared to what they did to poor Thing.
Originally part of an Flintstones double-feature with the Fred and Barney Show, The Thing starred the titular Fantastic Four member all on his lonesome. But instead of the lovable Yancy Street goon Ben Grimm, the superhero in question was just a shitty teen who gets his Thing powers from two magic rings. This twerp can Thing-out any time he wants by clasping his rings together and yelling "Thing Ring, Do Your Thing!"
Not only does it look goofy as hell (why does the ring also supply him a magic speedo?), but turning Thing's curse into an on/off switch obliterates any nuance the character had in the first place. It's like throwing Spider-Man into a steampunk apocalypse.
Spider-Man Unlimited was an attempt at taking the iconic titular character and putting him in a completely new setting. Like that time Heinz added green food coloring to ketchup, it was a bold move that ultimately did not pay off.
The premise of the show is about J. Jonah Jameson's astronaut son going on a mission to a new planet that has been discovered. Venom and Carnage sneak onto his ship in order to sabotage the mission, but Spider-Man thwarts them with an assortment of deadly quips and barbs. The symbiotes' interference means contact is lost with the ship, and an enraged JJJ of course puts the blame on Spidey. With everyone in New York out to get him, Spider-Man has to get on another rocket ship and travel to this "Counter-Earth" to rescue Jameson's son and clear his name.
It's pretty convoluted, but at least we get to see Venom doing the fusion dance with Carnage.
On Counter-Earth, which is on the opposite side of the sun, an X-Men/Thor villain named The High Evolutionary took over with a race of animal hybrids/Google Search History poison known as the Beastials. Humanity has scraped together an outmatched resistance to stop him and his super powered minions, and Spider-Man is basically the rebellion's John Connor. It's at this point that Spidey dons a goofy web cape, and starts hanging out with bizarre Counter-Earth versions of established villains.
The Green Goblin, now a good guy, kind of resembles one of the tinkerers from the Warcraft games.
If reading that description made you think "That doesn't sound anything like Spider-Man" then congratulations, you should have probably been in charge of production. The biggest mistake they made was making something that was so different from the established stories that it may as well not be attached to the character at all.
While you have to give them credit for trying something new, on the other hand, "a futuristic humanoid horse being dragged into a pit by disembodied hands" definitely does not fall under "does whatever a spider can."