Blackwater fever is a complication of malaria. It is characterized by hemoglobin in the urine. The hemoglobin in urine gives its characteristic black color. The febrile intravascular hemolysis along with anemia results in hemoglobinuria. Reference: https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2180-1#:~:text=Blackwater%20fever%20is%20a%20complication,its%20pathogenesis%20remains%20incompletely%20understood. Image via: https://www.semanticscholar.org/paper/An-unusual-case-of-blackwater-fever-Biswas-Chakraborty/1b0a6afdeea3c5a1cf72fbdfb01b525c223166f0