no hes a alien or a monster
You must mean the robot that worked at his Fortress of Solitude in the animated movie "Superman/ Doomsday".
Superman and Doomsday were equally match if not more so Doomsday. But Superman had advantage of will power, as he always does. Superman used up all his (solar) energy with his final punch too take down Doomsday. Who also did a final punch to take down Superman, who had no energy left so "killed him" (As we know later it didn't) Not worth thinking into. The writers wanted Superman to die and they couldn't leave Doomsday undefeated by Superman, so it was only way to write it.
Superman/ Doomsday (2007)
Adam Baldwin
yes
It already has, you can find it at tubeplus.com
"Superman Lives"
no hes a alien or a monster
Doomsday killed him in the 1992 story-arc The Death of Superman
Doomsday is often portrayed as physically stronger than Superman due to his ability to adapt and become immune to attacks that have defeated him before. However, Superman has defeated Doomsday in various storylines through teamwork, strategy, or sheer determination. So, while Doomsday may have the edge in raw power, Superman's resilience and heroism make him a formidable opponent.
Doomsday. 'nuff said
Yes he killed Superman.