Formication -- spell it carefully, now! -- is an "abnormal sense of ants crawling over one's skin." It's from Latin formica, meaning "ant," and no relation to Formica kitchen countertops.
Remember a while back when I was marveling at how scientists measure the size of ants' heads? Well, here's an even more mind-blowing story. Seems a German team has discovered that ants find their way back to their nests across long distances by somehow counting their steps. The scientists discovered the apparent existence of these "internal pedometers" with two experiments: They either cut off the tips of ant legs (in which case the ants walked the same number of steps back to the nest, and thus came up short), or they fashioned little anty "stilts" for them out of pig hair bristles (in which case, the ants, walking the same number of steps, overshot their nest).
If I hadn't already read all that business about ant-head measurments, I might have taken all this with at least an ant-sized grain of salt. And there's video of the little things on stilts accompanying an article in New Scientist, as well as an audio report on NPR.
Fascinating to learn about this, of course. But I have to say, as far as I'm concerned, the whole thing is giving me a bad case of formication.