Put the summary of the bug you're having here
When riding a horse, your head can go straight through leaves without taking damage (possibly another glitch). Using this, its possible to x-ray through the tree (after turning graphics to fast). This could be extended to x-raying for caves, by placing a leaf block underground.
What I expected to happen was...:
Well, I actually thought I would take damage, but at the very least my screen would turn black

What actually happened was...:
I was able to see through the tree

Steps to Reproduce:
1. Tame a horse (duh)
2. Put a saddle on a horse
3. Ride the horse to a spot where you're head will be inside of a leaf block.
4. Turn your graphics to fancy.
PS: For the first screenshot, I'm inside of the tree. For the second, I just backed up.
PPS: I set the Security Level to private as it is a glitch that could be abused. Is that correct?