Teaspoon

The aliens don’t like water.
And for good reason. All it takes is just a little water to kill them. A teaspoon.
Walking around outside without an environment suit is like torture.
This is why it’s so important to keep them under guard around the clock.
People can be such jerks.
Tearing off a suit, knocking an alien into the water.
The worst was when some joker hacked the fire suppression system in the alien embassy.
The United Nations buildings ignored fire codes, but not the embassy.
That’s how the war started… and the oceans, rivers and lakes slowly vanished.