Have you ever had one of those mornings when things just didn’t go right? You wake up after a night of tossing and turning because you have a big appointment of some sort, you stagger to the bathroom sink to brush your teeth and then you see it; a giant whitehead glaring back at you in silent mockery.

It’s too big for anyone to ignore and there simply isn’t any way to cover it from view. You’re going to have to go out into the world with an unfortunate situation glowing like a beacon of humiliation for all the world to see.

I can’t imagine that there is a single person out there who hasn’t had that experience. All too often, this first happens to us when we are in high school and it can be absolutely devastating to deal with. By the time we’re older, we understand that these things happen, but it is still an unpleasant experience whenever it happens to you.

Imagine that particular feeling of self-conscious discomfort and then multiply it by about, oh, a million. Then add in a level of physical discomfort that is, frankly, unimaginable and you will have a scenario that I witnessed out on my porch railing just a week ago. If you are a squeamish person, you may want to sit down, if you’re not already, before reading further.

In the wild world right outside our back doors, there are horrors that are almost unimaginable for a human. There are myriad creatures that want to make a living by feeding off you and they have some truly diabolical ways of doing this. Mosquitoes have long needle-like proboscises that penetrate the skin and deliver an anticoagulant to keep your blood flowing as they siphon it away from you. Leeches produce a powerful anesthetic so you can’t feel it when they start chewing on you. And so on.

But there are horrors out there even more repugnant, and as an example, I present to you the botfly. This creature is a true parasite. It lays eggs that are sensitive to heat and when the warmth of the intended victim is sensed, the egg will hatch and the small larva inside will start burrowing into the skin. Once the larva has reached the appropriate depth, it will stop and set up shop.

This behavior is made easier by the fact that the larva is covered with rows of little spikes that help to anchor it in place. The problem is that the botfly needs to get out of its host, so it needs to stay close to the surface and then actually maintain an opening in the skin to serve as an escape hatch as it reaches the final stage of maturation. It doesn’t want to leave prematurely, for it feeds on the body fluids of the host organism, but it needs to be able to pop out at just the right time so it can pupate in the soil of the forest or field in which the host lives.

Well, I happened to notice a young squirrel at my feeders that had something odd on its chest. I normally don’t look too carefully at squirrels, but this one caught my eye because of a large lump near its left armpit (if squirrels have armpits). Then I saw the telltale mark that told me the whole horror story — a small black opening on the side of the lump that could only be the escape hatch of a large, healthy botfly larva.

I was lucky that the location of the lump had caused the movement of the squirrel’s front leg to wear away the fur surrounding the hole. This made it easier form me to see what I was looking at, but it must have been horribly uncomfortable for the squirrel. Imagine having a growth the size of a lime in your armpit and you’ll have the right idea.

It took me quite a while to get a decent photo of this condition because the location of the botfly larva kept it hidden from view for most of the time. However, when the squirrel moved in just the right way, I had a chance to take photos. All I had to do was take lots of pictures every time the squirrel took a step, and then hope that one came out. Eventually I got lucky.

So now imagine that you wake up, stagger to the bathroom sink to brush your teeth, and see a huge distended bump under your skin that has a circular black hole in the middle of it. Then imagine that you can feel a living thing squirming around under your skin, but because it is armed with rows of spikes that dig into your flesh, it will be very difficult to remove. Disgusting, right? Aren’t you glad you don’t have to experience that in your life?

Well, hold onto your hat. There is a particular species of botfly called the human botfly that specializes on parasitizing humans. This species can be found in southern Mexico, throughout Central America and almost all of South America. The only portion of South America not afflicted with this particular nightmare is Patagonia (the southern tip of South America shared by Argentina and Chile).

Well, that’s about all of that I can stand to think of on that particular topic. Nature isn’t all flowers and butterflies, and I wouldn’t want to be accused of ignoring “true nature,” but I think I need to write about flowers, butterflies, or something else more pleasant and inspiring next week. Until then, count your lucky stars and maybe give a second thought to that South American vacation you’ve been planning.

Bill Danielson has been a professional writer and nature photographer for 21 years. He has worked for the National Park Service, the U.S. Forest Service and Massachusetts State Parks, and currently teaches high school biology and physics. Visit www.speakingofnature.com for more information, or go to Speaking of Nature on Facebook.