OK I'm cheating slightly, as the photo was taken through a hand-lens. To the naked eye,. this is what it looks like:
Horrible, huh? A disgusting growth on the leaves of an oak tree, all diseased and rotten.
But not at all - when viewed through the hand-lens, you can see that what appear to be scabby pustules are actually tiny little homes, made by a Gall Wasp whose proper name is Neuroterus numismalis. (OK, I had to go and look it up on Wikipedia, I admit it.)
Amazing stuff, huh?
And to see this for yourself, all you need is a simple hand lens, available on Amazon for about £2.20 for a 20x ("twenty times" ie makes things twenty times bigger) folding lens. You can get 10x lenses, but you may as well get the better one while you are at it.
This is what a standard hand-lens looks like: it folds into itself to protect the lenses, and if you want to look like a
This is to prevent you putting it down while out "in the field" looking at things, and losing it in the long grass. OK, it does make you look a bit nerdish, but if you are lucky you will get other botanists (or bug-ists, I suppose) running up to you, saying "ooh, ooh, whatcha looking at?"
Of course, the down side of that is that you will be expected to learn a few names of things..
"Silk Button Spangles" you can announce, with authority. "They only manifest on oak leaves, you know." (True.)
And once you get a hand lens, you will find yourself looking at things, and being amazed at the detail you can see on the most ordinary of plants.
Actually, even looking at your own fingerprints through a hand lens is fascinating...
..and in case you are wondering, I took the close-up photos using my cheap phone camera, by simply holding the hand-lens over the camera lens, and getting really close to the leaf. Easy!