If there’s one multicellular organism that will survive the nuclear holocaust or the complete destruction of the ozone layer, it is the tardigrade, or water bear. They can curl up into a ball and survive being in a vacuum, -200* C, and 1000x the radiation dose that would kill a person, among other things. more info
I, for one, bow down to our tardigrade overlords, who will probably be swimming around in pond scum long after humans have vanished from the earth.
I’d also like to work in the lab that sits around all day thinking of ways to kill them. I think I’d try sodium hydroxide next – do you suppose they could survive in drain cleaner?
Rather mundane and pointless, but that’s my zoology fact for the day.