Doomsday was created through the cloning of an infant and having him killed over and over again by one of the most dangerous species of the universe and in one of the harshest habitats in existence, prehistoric Krypton. As such, the infant evolves and returns to life, becoming resistant or immune to whatever killed him before. After the Radiant killed him the first time they fought, Doomsday grew immune to the former's energy-projection, and even managed to withstand Darkseid's full Omega-Effect.[17] The amount of damage dealt to Doomsday determines the length of time it would take to fully recover. During his outwardly undamaged death at Superman's hands, he only needed some days to recover, but when Imperiex reduced him to a skeleton, it would take months. Although he may never return if totally disintegrated to nothing and totally destroyed with no remains or not even a single atom of him left. His entombment in a Calatonian burial suit and metal vault lasted thousands of centuries: after being killed by the Radiant and subsequently undergoing the impact of the casket on Earth, his body was sealed underground in total darkness. Deprived of solar energy to nourish his Kryptonian anatomy, he could only revive extremely slowly and naturally.[citation needed]
Doomsday can also develop/evolve resistance from ordinary injuries. Superman once used a sound gun to greatly discomfort him, but Doomsday's auditory canals closed up, making him impervious to Superman's weapon.[17] Waverider once paralyzed Doomsday with chronal energy, but the second attempt backfired.[17] In essence, Doomsday gradually turns more invulnerable if not injured beyond his ability to recover, which is so far undefined. Doomsday has also developed weapons and abilities that counters the powers of an opponent. He managed to cancel out the pure-energy Radiant by slamming into him; to greatly extend his claws and develop a poison to strike Superman in flight and reel him in;[17] or breathe flames against the fire-sensitive Martian Manhunter, and apparently neutralize his defensive phase-shifting power.[18] Doomsday's skeleton protrudes through his skin in razor-sharp spurs which provide protection to his few vital organs (brain, eyes, nervous system), and act as clawlike weapons on his hands, elbows, and knees.
Doomsday possesses extreme superhuman strength that, variable as it is, at one point enabled him to effortlessly stand his ground against the entire Justice League, including Superman and Orion.[19] He was able to break Superman's left arm with limited effort, as well as outmatch and beat Darkseid unconscious in combat.[17] However, his strength has limits: the immensely strong Calatonian alloy cables, in which he was entombed, continued to partially restrain him during his initial rampage on Earth. Needing the equivalent strength of a bulldozer to break; It was never stated how long he had struggled to free his left hand before his escape.[citation needed]
Doomsday is immensely resistant to heat, cold, and conventional damage, allowing him to survive on the most inhospitable worlds, or in the vacuum of space. His superhuman endurance and invulnurability were able to withstand Darkseid's full-powered "Omega Effect" without any shown damage.[17]
Doomsday possesses seemingly inexhaustible stamina, and was not noticeably slowed down from fighting Superman for an entire day. His speed and agility are vastly disproportionate to his bulky stature, and he has been able to match Superman in this regard, once even managing to grab the Flash while the hero was in motion.
Doomsday has a highly accelerated healing factor that allows him to quickly regenerate from most damage. When his side was cut by Superman with a plasma sword, it closed within moments. As a result of his engineering, Doomsday does not need to eat, drink, breathe, or sleep, and his body is almost solid mass with no internal organs.[17]
@ "looks like" 