One of the original five X-Men, Iceman is a mutant with the superhuman ability to project intense coldness from his body. Now with this great power, the problem with Iceman is that he has always feared his power and thus lacked the confidence to really learn his true extent.
As most would know, Iceman’s original form was made out of snow. This was during the period when he was still developing his powers and wasn’t too strong either. It was after Cyclops suggested that Iceman should refine his powers that he gained the ability to not only cover his body with ice, but to actually become organic ice. Iceman is virtually indestructible in this form, which allows him to reform his body if it become shattered. He has been incinerated while in human form, and was able to rebuild himself. In his ice form, he is able to use the moisture in the air to form spikes, shields and attach other extra appendages to his body. It is currently unknown if Bobby would be considered immortal though recent events would suggest that this is highly possible or he can achieve that with enough practice.
Iceman is one of the few who actually went through a secondary mutation which basically made him “living ice” at the cost of him not being able to change back to human form. He was suck in ice form for some time until Emma Frost unlocked his mind since it had seemed he was subconsciously preventing himself from changing.
Then Iceman returned to the X-Men, to lend his services to Wolverine at his new school for young mutants and serves as the school’s bookkeeper. During his time at the school he had been thrown into situations that pushed him to unlocking more of his potential such as being able to create “Icemen”, literally a whole army of himself in which he controls all their actions. He has shown the potential to teleport and even increase his size to that equaled to Giant Man. In Avengers Vs X-Men, you see how far Iceman has come just for the fact that during this all out war, he was seen taking on the Red Hulk all by himself and seemed to be able to hold his own with ease.
Now we have Astonishing X-Men #62, being the aftermath to X-Termination, where Beast stuck a piece of the death seed in Iceman’s back. He doesn’t realize this, but it’s slowly changing him for the worst. It starts with endless nights of sleep to random bursts of anger as the seed corrupts him. You see his decent into darkness because this here is not Bobby. As of now he is not himself anymore and what we are more familiar with is the wisecracking mutant that doesn’t take much seriously. It left him empty and destructive causing what they call an Apocalypse.