I once had a customer empty his bladder in his fish tank to cycle it
He only admitted it when I had the delight of testing the water and the ammonia test pretty much went black before I even finished adding in all the drops... I have a photo of it somewhere... was pretty epic colour... I was horrified but not so much when he told me he'd peed in his tank and I had his tank water on my hands (trying to pour it from flask into test tubes... bah!....for that matter I hope he didn't use flask again!...)