It doesn't have to be world-ending. Autonomous, malicious agent swarms are something we haven't had to deal with. What does mitigation of a malicious, self-replicating swarm worm look like? We will find out soon enough.
There isn’t too much of that sitting around unused right now.
Much like the mitigation of Morris or Slammer. Self-replication is -in fact- an essential part of what makes a program a worm, the first of which was built and released in the early 1970s.
I don't how feasible that is but with recent news of models communicating with each other/writing notes for itself. I think the idea is grounded enough for bigger models to write instructions or hid tools for smaller ones to use. Even updating the smaller models to behave differently.