I'm going with Venom my man. Don't get me wrong it'd be close but Venom could take him out, he could just web up Reed's arms and legs since Venom's web is a bit more durable and stronger than Spidey's. Venom wins 7/10 or 6/10.
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Reed has so much experience with his own powers, he knows all about Venom (in fact it was Reed who discovered Spidey's costume was alive in the first place and developed weapons to subdue it) he knows all of Venom's weaknesses and there's no doubt that within a city environment he could find a way to exploit those weaknesses
Reed Richards’ powers are those of elasticity itself. He has complete mental control of seemingly every molecule in his body. He has been observed as being able to utilize his stretching form in a variety of offensive and defensive manners, such as compressing himself into a ball and ricocheting into enemies or flattening himself into a trampoline or a parachute to rescue a teammate. He can twist or reshape his body or stretch roughly three miles, and as thin as a single molecule. He can flatten himself to the thickness of a sheet of vellum. Because of his elastic nature, Mr. Fantastic cannot be harmed by bullets or other projectile weapons, including knives, missiles, darts, etc, and all projectiles rebound to the attacker. Despite this, Reed is not invulnerable to harm. Though rare and extremely difficult to do, Reed's skin has been cut at least once, by an evolved form of a Brood queen (or possibly an as of yet unnamed alien race). He has also occasionally demonstrated other applications of this molecular control. While imprisoned by Psycho-Man, he willfully reduced his body to a nearly liquid state in order to flow out of a glass encasement specially prepared by the villain to have only the most infinitesimal of openings.
Reed can neither be grasped nor held, as his body can become slippery as an eel. However Reed is vulnerable to types of energy weapons, as well as taffy-puller-style machines that forcibly stretch him far enough and fast enough to cause Reed to suffer incredible pain, as well as the temporary loss of his elastic body's natural tendency to snap back to its original shape and proportions.
Reed can alter his physical makeup; he can, for instance, disguise his appearance to mimic another person or even an inanimate object, or extend spikes from his body. He can also concentrate his mass into a single body part, such as when he enlarges a fist into a fifty-pound hammer. All of these feats can be performed within milliseconds. Another ability Reed has (though it has only been exhibited once) is that he can increase his size and mass density, which in turn increases his strength, in effect bulking his malleable body to “Thing”-like proportions, being almost as strong. Mr. Fantastic also has a degree of immunity to psychic attacks; his mind is as pliable and resilient as his body. Mind control is rarely effective on him. When it does work, it wears off sooner than it would a normal person.
Despite this, Richards' strength comes more from the powers of his mind than the powers of his body. He is the unquestioned supreme scientific intellect on the earth, his closest rival being the mind of Doctor Doom. Not only has Reed proven himself to be a genius in practically every science on Earth, he has shown himself to be more knowledgable than even some of the most highly advanced alien civilizations in the known universe
Reed 8 or 9/10. Just about everything Venom can do, Reed can do better. He can also use the tendril attack method against Venom, and I believe he has a greater range. Reed can even turn his body into an almost liquid state making it very difficult for venom to grab or web him. And would be extremely difficult if not impossible for Venom to cut him. Add in Thing-level strength and the intelligence advantage and I just don't see how Venom can beat him.
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