I made these to be a flag of evil or a flag of the enemy. Can be used for fictional Obviously Evil countries or for aggressor aircraft.
Which one do you like better?
Top one is simpler and easier to recognize at a glance. It also implies danger instead of death, which covers a larger group of enemies since many conflicts don't involve death or even violence.
I prefer the first icon for the same reasons that snooggums brought up. It's simpler, its solid color fits the rest of the design better, and it's more widely applicable.