KrisKing said:
Get Dr Manhattan to just explode him haha.
Harder question, how do you kill Dr Manhattan? :|
Good question. I'm nowhere near as smart as Ozymandias, he is the smartest man in the world after all, but he was short sighted.
Instead of just spreading out Tachyons (the theoretical particle that travels backwards in time) to prevent Dr Manhattan from looking into his future to see Ozy's plans, here's what he should have done:
Set up a tachyon bomb (or beam or whatever) to use on Dr Manhattan instead of hitting him with the I-Field Subtracter which was what made him in the first place.
Dr Manhattan can see his future and past both but he's never displayed any ability to time travel. If he could time travel he'd just go back to the 60's and kill Ozymandias before he ever had a chance to set in motion a plan to destroy New York.
SO, the answer is to use the tachyons to (hopefully) send Dr Manhattan as far as possible back in time.
Dr Manhattan would probably survive all his molecules being sent back in time.
Hopefully he'd go on to create life, like he said he was going to and discover all the possibilities and motivation for what Ozy did by the time he reached the moment he first disappeared.