Used with malicious intent or as a hilariouspractical joke, a piss brick is a frozen sheet of urine most often prepared in a shallow pan. The brick is then slid under the door of the victim's residence. In the most glorious of outcomes, the urine is absorbed by carpet and establishes its long-lasting odor.
The small yet numerous particles of urine that are reflected back at you when you pee into a urinal/toilet bowl. This phenomena usually happens when too much force is exerted when trying to force the urine out, causing the pee to have such a high velocity that when it strikes the surface (either water or porcelian) it instantly atomizes and reflects back toward the direction where it originated from.