Bearded Dragon diarrhoea. Can't even put into words how much it hits you, I pulled the muscles in my side with how badly I gagged/wretched. Their shit normally smells pretty bad, particularly if you clean it up straight away, but he had diarrhoea on my carpet when I let him run around, so went to clean it up straight away and, fucking hell, you could weaponise the smell. It was one of those that's so strong you don't really even smell it, you feel it. (top tip, don't overfeed lizards, they will commit war crimes)