I just really hate when deliberate cruelty is interpreted as 'life is unfair'. That is not life being unfair; that is a person being unfair. That is a person being malicious.
Madness string 83842
Based on the name and this situation, I assume a piss disk is when you pee into a shallow saucer, freeze it and then slide the frozen disk under a door so that it melts later and forms a pool of urine in someone's apartment.