Bubble Feeders.

Author's Note: In college I had a friend who taught bacteria to "eat" the toxic chemicals in effluent ponds. I was thinking about that when this story came to me.

*****
Everyone stared fascinated when the first Alien revealed themselves.
They looked like soap bubbles. Tiny little oily rainbow bubbles. Maybe about the size of an egg or a plum. At least at first they were that size.
Once they were around Humans, well, they grew bigger…brighter…heavier. Some would sink slowly to the ground, laying there like overstuffed water balloons of amazing colors.

The Aliens traded all kinds of Technology- just for the privilege of being allowed to float among us. If there was any kind of violence, or strong emotions- other than love or kindness- they showed up in droves. Some of them would fall to the ground with wet swampy sounds when they hit. After about a decade they stopped showing up. Finally, there were only a few of the bubbles left. Then…they left completely.

The Aliens left us a small note when they departed:

“Dear Humans,

We can’t thank you enough. We haven’t found many races that could feed us like you did. Certainly not this many of us... or for this long. As you probably now know, or have guessed; we feed off of all your negative emotions: anger, shame, guilt, fear, jealousy, revenge, frustration, hate. You were so filled with those things that our entire race has been satiated. We shall be able to live now for eons. We can’t thank you enough.

We leave you with the Technologies you so desired, and the Medical Advances that, for all practical purposes, will render you immortals. We leave you with what we always leave behind after we feed:

Peace.”

That note is inscribed all over the Earth. Underneath is a Peace Sign. Beneath that sign is what we said to the last of the Bubble Feeders when they left:

“You are welcome.”