I once lived in an apartment that had a few unadvertised occupants already, when I moved in. Insect squatters, yuck. The first time I noticed them was one night when it was raining. There were a few "winged ants" on the floor near the kitchen window in the morning. The window had been left slightly open, I figured they must have been attracted to the heat. They were squirming around awkwardly, as if they didn't know how to move in this environment. I didn't know it at the time, but these were the first of many, many termites I was to see over the next couple of months.
A month later, it rained again. This time, when I got up in the morning, hanging from the where the wall met the top of the living room window were two-inch "cocoons", or strips of seaweed, or something nasty. They were wet and dripping, and looked really horrible. I noticed that those same weird, winged ants, were all over the carpet next to that window. Suddenly, it all made sense. I alerted the apartment manager to the problem, and then spent an hour vacuuming up termites and wiping away the extended "hives". Apparently, the termites had begun expanding their colonies as they were pushed out by the rain. They had actually constructed chambers out of wood pulp, that hung down from the window sill, and had been amazingly industrious overnight. After wiping away the hive extensions, holes and tracks were plainly visible in the wall where the termites had emerged from.
Exterminators were brought in who applied liquid nitrogen (I believe, I may be confusing details here,) to the walls which killed the hives. It was a little unsettling to know a huge colony of freeze-dried insects was half an inch away from the wall, so we didn't stay there much longer.
In some cultures, termites are actually eaten, and even viewed as an aphrodisiac. The queens in particular are especially valued, and can sell for as much as $10 each. They are also used in a variety of health remedies in various cultures. I can think of few things more repulsive than the memory of that squirming carpet, teeming with hordes of termites trying to get back into the walls...