I’ve always hoped for a doomsday device that gives some warning.
We KNOW we’ll be dead in say, a month. But we’ll feel healthy for a good 3 weeks, before we sicken and die.
Leads to lots of entertaining drama and pathos. I’m kind of picturing something like “On the Beach”, but I don’t think nuclear fallout is reliable enough
So I gotta go with an airborne unbelevably contagious virus with 100% lethality, that survives easily in soil and water, AND immediately turns our piss magenta colored, so we know that the countdown has started.
Then 3 weeks of: revenge, repentance, reprobate behavior, whatever. The a choice of ending it quickly, or an agonizing death on the chance the YOU might be the FIRST to actually survive it.