Warning: Contains spoilers for Wolverine#20
The Merc with a Mouth, Deadpool, has the unique superpower of making everyone around him exasperated by his behavior, and no one has less patience for Deadpool's antics than the X-Man Colossus. Most of the time, the interactions between these two end with Deadpool broken, bloody, and generally humiliated. And their latest encounter is no exception.
The dynamic between the two characters was made famous by the first Deadpool movie, where Deadpool attacks Colossus and absolutely demolishes his own body in the process. 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. In the comics, the two have faced several times, and the results are always the same. For example, when Deadpool stages a fight with the X-Men to save their reputations from Norman Osborn's slander in Deadpool vol. 4 #18, by Daniel Way, Paco Medina, and Marte Gracia, he headbutts Colossus only to break his own face and bleed out so much that he blinds Piotr for a while. It does not work for long, of course, and it just makes Colossus angrier.
Breaking his arms, legs, or face will not stop Deadpool from trying. In a recent Wolverine comic, however, Wade finally has some measure of revenge against Colossus, but it does not last long. In Wolverine #20 by Benjamin Percy, Adam Kubert, Frank Martin, and Dijjo Lima, Deadpool is trying to stop Logan from getting himself and the X-Men in trouble with the U.S. government, which has stolen a severed hand of Wolverine's and is hatching some secret anti-mutant plan. When Logan arrives at the location of his hand, he finds a scene of carnage with bodies lying on the ground, including many robotic replicas of the X-Men. It turns out Deadpool is (likely) responsible for this, and he had particular fun destroying a Colossus robot, but then the body fell on him, burying the poor mercenary beneath. It's a pretty funny scene and it shows that Deadpool is destined to always be humiliated in his ongoing feud with Colossus.
The dynamic between the two characters actually goes beyond simple gags. Since his introduction, Piotr Rasputin has been defined by his dependable nature and no-nonsense attitude. Just like his skin, Colossus' personality is steel-like: he can be the most reliable ally but also the most relentless foe. Deadpool is his opposite: his personality is as malleable (not to say unstable) as his ultra-regenerative body. While Colossus almost never gets hurt, Deadpool is constantly shown with the most horrible injuries possible. It makes complete sense, then, that Colossus is often used in the comics as a foil for Deadpool's crazy antics.
It is also interesting that in current storylines Colossus is actually a traitor to the mutant nation of Krakoa after his brother Mikhail tampered with his mind to make him a Russian sleeper agent. Considering that Colossus has always been the most incorruptible and honest of the X-Men, it would be really entertaining if his treason was discovered by Deadpool, who recently got his own much-coveted ticket to Krakoa. This would certainly make Wade feel much better than simply destroying a robotic version of Piotr, and Deadpool could finally get some modicum of revenge for the constant humiliations suffered at the hands of Colossus.