I almost missed it. If I�d looked away as I closed the refrigerator door, 1 would have. But the light didn�t go out. Poly explained later that they (he? it?) had shorted out the switch (at some personal sacrifice) to keep it on, but I�m getting ahead of myself.

People joke about whether the refrigerator light really goes out when the door closes. If you look, though, you�ll see it turn off just before that, when the door pushes the switch in. But this time it didn�t. I�d been getting a late-night snack, didn�t bother turning on the main kitchen light, and the refrigerator light stayed on right up until the door seal hit the frame.

�That�s odd,� I said to myself, aloud. I do that. I opened and closed the door again, watching closely. The light stayed on.

I didn�t know that the closed refrigerator was still illuminated, any more than Schrodinger knew if his cat was alive or dead, but a half-dozen schemes to decide came to mind. If I could find my meter I could check the current draw, but I�d have to drag the fridge away from the outlet. There was enough shelf space between the milk carton, the pickle and jam jars, and yesterday�s leftovers to put my camcorder, but the battery wasn�t charged. Out in the garage I excavated the weed whacker and unreeled a foot of monofilament from the business end. Now I had a crude fiber-optic cable. I closed the refrigerator door on the nylon line, one end protruding. The tip glowed; the light was still on.

I opened the door and squatted down to examine the switch. I pushed it a few times to no effect. 1 didn�t want to commit appliance repair at this hour, but neither did 1 want to leave the light on all night. As I reached in to unscrew the bulb, I saw Poly.

My first reaction to the yellow-green slime growing on the fridge wall was to recoil in surprise and disgust. I�ve heard of weird things growing in the back of the refrigerator, but this! Resigning myself to the cleanup job, I moved the big pickle jar aside, then went to get a sponge and disinfectant spray.

Back at the fridge, I noticed that the slime mold�it resembled chartreuse pudding�now had a raised pattern on its surface. I knew a little about slime molds�that they can move and change shape�but I�d never heard of one creating on itself the diagonally barred circle, �, that usually means NO. �Odd,� I said to myself again. And yes, again aloud.

I started to reach in with the sponge, and the slime rippled and changed as I watched. I hadn�t thought they could move that fast, and was even more surprised when the surface formed, in raised ridges, the letter N. It held that for a few seconds then morphed to show the letter O.

���No�?�

The slime mold raised two dots and a curved line within the O, like this: ☺. A happy face? Had it heard me?

�Can you hear me?� 1 must be crazy, I thought, talking to a slime mold.

The mold shaped the letter Y, then E, then S. Then: D, O, N, T, then went flat for a bit, then H, U, R, T, flat, U, S.

���Don�t hurt us�?�

�☺�

�But I only see one of you.� A detail like that shouldn�t have worried me when here I was talking to a slime mold, but 1 was grasping at the mundane. This was getting decidedly weird.

�C, O, L, L, E, C, T, I, V, E,� flat �O, R, G, A, N, I, S, M� it spelled out. It was getting faster.

�You�re a collective organism?�

�☺�

�But, what are you? Who are you?�

�Physarum polycephalum sapiens,� it said. Well, spelled out.

�That�s quite a name.�

�Don�t have name. Intelligent slime mold.� How about I just call you Poly?�

�☺�

So, I had an intelligent slime mold named Poly in my refrigerator. I had too many questions to know where to begin�most concerning my own sanity. I needed more data.

�Excuse me a moment,� I said. Politeness, even to a slime mold, couldn�t hurt. �I�ll be right back.� I headed for my computer.

There was no such thing, according to Google, as �Physarum polycephalum sapiens.� There are many kinds of slime molds, organisms with many nuclei in a single blob of protoplasm. Plain Physarum polycephalum is a yellow slime mold, easy to grow in the lab. It had been the subject of numerous experiments involving intelligence, of a sort. Years ago, Dr. Toshiyuki Nakagaki in Nagoya had shown that a slime mold could determine the shortest path in a maze. That might be a chemical tropism rather than �intelligence,� but I�m no expert. In 2006, Klaus-Peter Zauner at the University of Southhampton built a robot controlled by Physarum polycephalum. But that mold�and the robot it controlled�avoided light; why was mine huddled up to the bulb in the fridge? Warmth?

I�d have to ask it.

�4 NRG.� Now it was using texting shorthand. I�ll translate.

�For energy? Photosynthesis?�

�☺�

�How?�

�Absorbed chloroplasts.�

It was much greener than the web pictures I�d found. That�s when I noticed that the salad greens in the vegetable crisper were now salad whites. I�d have to toss those.

�But why are you in the fridge?�

�Need cooling.�

That made sense. This communication must take a lot of energy. I didn�t know how it was intelligent, but I knew that our brains and computers both need considerable cooling. So too must intelligent slime molds.

We chatted in that vein a bit. Poly explained how they (he, it, whatever) had gimmicked the light switch, and assured me that it was reversible.

Slowly I realized that 1 was missing the big questions.

�Where did you come from?� I asked. �How did you get here? What do you want?�

�Too much philosophy. Want to go home.� �Oh.� I was tired from the late hour and my mind was numb. In my dazed state I didn�t ask where �home� was. Another planet? A parallel world? Dr. Nakagaki�s lab?

�How will you do that?�

�Recharge,� it began, then �O�, �o�, �.�, �*� followed. This last sequence was animated, not spelled out. The circle shrank to a dot, then radiated out and went flat.

�You explode? Disappear? Beam up? What?�

�☺�

�But��

As I watched, the raised circle outlining the face flattened, fading, leaving just the eyes and mouth. Then the eyes went, leaving just the smile. A Cheshire slime mold.

That was more than I could handle. As I closed the refrigerator door, I said to Poly: �Okay. But when the last of you leaves, please turn out the light.�