They were a group of intergalactic refugees. Wanted to the use the earth as an apolitical zone for creatures without a planet. Did you ever seen the movie "Casablanca"? Same thing, except no Nazis. We agreed, and we concealed all the evidence of their landing.

Tommy Lee Jones - Kay

“They've been planning this for a million years. They defeated the greatest power in the world in a couple days. Walked right over us. And these were only the first. They'll keep coming. This is not a war. This is an extermination.”
Tim Robbins - Harlan Ogilvy

“- Frank the Pug: Listen, partner. I may look like a dog, but I only play one here on Earth.
- Jay: OK, wipe your mouth.”
Tim Blaney - Frank the Pug
Will Smith - Jay

"Prepare to die, Earth scum! Prepare to die, Earth scum!". I'm gonna make sure they carve that on your tombstone!
Tony Cox - Pez

“One hundred billion trillion planets in the cosmos. You want to know, don't you, why they keep coming here?”
Philip Anthony Hopkins - Sir Edmund Burton