As a final favor to Magneto, he agreed to teach the next generation of mutants with his wife. Colossus came out of retirement two times. The first time he was injured so severely only Magneto's metal powers kept him alive. Colossus could not transform back to his human self without risking death.
In his human form, he is still exceptionally strong and in superb physical condition, though not superhumanly so. He has completed college-level courses at Xavier's school. As the unstoppable Avatar of Cyttorak, Colossus gained additional superhuman strength and resistance to injury, as well as other mystical powers.
The longest time he has remained in armored form by choice so far has been five days. Once in his armored form he remains so until he consciously wills himself back to normal. If he is rendered unconscious, however, he spontaneously reverts to his normal form.
Colossus can convert the tissue of his entire body into an organic, steel-like substance analogous to osmium and to carbon steel that grants him superhuman strength (Class 100) and a high degree of imperviousness to injury.
Colossus Anatomy Explored - Can He Liquify His Body Metal? Is He Hollow From Inside?
Can Colossus beat Thanos?
One of the most physically powerful X-Men, Colossus is a force to be reckoned with. He would be able to put up a good fight against Thanos and even get close to beating him but he wouldn't be able to keep Thanos down and that would be a problem.
As a final favor to Magneto, he agreed to teach the next generation of mutants with his wife. Colossus came out of retirement two times. The first time he was injured so severely only Magneto's metal powers kept him alive. Colossus could not transform back to his human self without risking death.
That very same power is a veritable death sentence against Magneto. While he has fought Colossus before, Magneto has been very kind not to rip him to shreds. After all, it would take little more than a thought for Magneto to turn Colossus' entire body into shrapnel.
Upon seeing Colossus, the monster stabs through Colossus with his adamantium claws. Even though Wolverine was transformed into a Wendigo, the moment illustrates just how powerful Logan's adamantium claws are. He pierced all the way through Colossus organic steel skin - that's no small feat.
So while Juggernaut is much more powerful, and would normally be able to win in a fight, Colossus could convince Cyttorak to transfer his power, or even cut off Cain Marko's connection to Cyttorak. Cain Marko would be left as a normal human. Colossus would still be a powerful mutant.
When Piotr is in his metal form, he no longer needs to breathe. This makes him far more versatile than you'd think. Since he doesn't need to breathe, he can survive in atmospheres without oxygen, traverse the bottom of bodies of water and even survive in space for a short while, but not indefinitely.
Deadpool does his best to harm Colossus, but the metal skin and muscles of the Russian mutants mean that Wade can only break his wrists by punching him.
After grabbing the former Juggernaut, Colossus realizes he can't stop him and ends up pushing him more than 600 MPH. The Serpent has to intervene and teleports the hammer-wielding villain out of harm's way, knowing he would be defeated if he kept fighting the unstoppable Colossus.
Issue #3 of the Official Handbook of the Marvel Universe mentions that Colossus is made up of the dense metal osmium, which is actually derived from another dimension. Colossus' connection with the other unspecified dimension can reshape all of Peter's bodily functions in organic ionic osmium materials.
Wolverine, given enough time, could defeat Colossus in a fight using only his claws, but he would have a terrifically difficult time doing so; the latter's skin is made of adamantium, same as Logan's claws, and even a demon-controlled Wolverine can do very little against him.
In fact, the two heavyweights have actually squared off before, and the result was far from a tie. In DC Versus Marvel #1, Superman beat the Juggernaut with a single punch.
3 Magneto. Much like other mutants who are not physically strong but are capable of great physical feats, the Omega-level Master of Magnetism could defeat the Juggernaut in any number of ways.
The two brawlers have fought beyond these two encounters, but these two fights establish a few hard facts: the Hulk can be overpowered by the Juggernaut; the Hulk cannot consistently stop the Juggernaut; and most importantly, the Hulk's strength, even at maximum, cannot harm the Juggernaut at his maximum power.
Colossus does have a huge weakness in the form of Vibranium. Any sort of physical contact with Vibranium will force Colossus to revert to his original form. This forced reversion doesn't last for long and he can return back to his armored form once he is away from the Vibranium.
Yes, Deadpool feels every bit of pain as normal humans do. However, his regenerative ability allows him to heal from all injuries. While Deadpool can heal quickly, he isn't indestructible. His body restores, but he does endure pain as much as a regular human would upon a similar injury.
While Deadpool 2's Juggernaut was doubtlessly powerful, the original version is an unstoppable force of nature. In Uncanny X-Men #183, Juggernaut destroyed Colossus (and the bar they were in) yet again, and even when both combatants were magically amped in Fear Itself Colossus never got a clear victory.
Colossus' organic metal is strong enough to fend off bullets or even attacks from weaker metals, but it leaves the X-Man vulnerable to attacks from both vibranium and adamantium, meaning heroes like Captain America and Wolverine could kill Colossus with little effort.
