I was going to suggest it's just hormones and he's restless, hence the
black beard and the glass surfing. I doubt it's parasites, but a fecal test is always good to do if you can. The only advice I'll give you is that if he continues to eat and act completely normally, and then you get a fecal test done and it comes back for some type of parasite like coccidia or pinworms, but they are in the low or moderate range, do not medicate him again, he doesn't need it! Lately there has been so much over-medicating for parasites by vets and it's only causing them tons of problems they didn't have in the first place. It's normal for bearded dragons to have coccidia, pinworms, and other parasites and bacteria (like Pseudomonas, that's the new one they're starting to medicate for, completely unnecessary) in their gastrointestinal tracts pretty much all the time. However, unless the test comes back as the parasites or pinworms being in at least the high range, or unless your beardie is actually showing active symptoms and signs of being sick like a lack of appetite, lethargy, not basking, very runny stools or stools with blood in them (not formed stools with a lot of fluid coming out along with them, that's simply a sign of good
hydration, the actual poop needs to be mushy and not at all formed), they do not need to be put on any medication for anything. It's unnecessary if they are acting normally and will only cause them to become sick, stop eating for quite a while, cause them to lose weight, and it turns into a cycle of meds causing sickness, then they give more meds because they thing it's being caused by the parasites, then the new meds cause more sickness, etc. It's getting way too common. Your boy looks very healthy, of a good weight, and he's only 2 years old, so he's right at the correct age for his hormones to be raging, which is exactly what's going on...