The Ursaens, if you can call them that, have already seen our 1960 television programs,
including "Leave it to Beaver", "Have Gun will Travel", "The Twilight Zone", etc...
Worse...They've already seen Elvis shaking his hips 4 years ago on the Milton Berle Show;
they think our women are as stupid as Lucy, and they think our men are as fat as Ralph
and as stupid as Morton.

To make a long story short, the Ursaens have decided, for the good of our galaxy,
to wipe us out of existence with hundreds of antimatter missiles.
The weapons will arrive on target by means of Bussard-type interstellar ramjets with the next 100 years.
Tell your grandchildren you love them.