Diplomatic Immunity by Robert Sheckley. Short summary

5 seconds

An alien ambassador demands that the Earthlings join their power. The humans don’t want that and try to kill the ambassador, but he is invulnerable. However, they find a way to destroy him.

1 minute

An alien ambassador arrives on Earth demanding to join their power. The Earthlings didn’t want to, but the ambassador signaled the higher-ups to find Earth.

The Earthlings tried to destroy the ambassador, to interrupt the transmission of the signal to the aliens. They shot, burned, and killed with gamma rays, but the ambassador remained alive.

The alien explained that he had diplomatic immunity, allowing him to turn into the weapon they wanted to kill him.

The ambassador was poisoned with acid, gassed, and hypnotized, but he seemed invulnerable.

However, the Earthlings figured out that it was necessary to destroy the ambassador’s structure with a semblance of cosmic chaos. They artificially created it and destroyed the envoy.

And then the Earthlings dispersed to rest so that tomorrow they could figure out how to disguise the planet.