|the white rat|
The white rat, caught by Screed in "Fever".
In the Season Three episode "Fever", a white rat is one of many research animals that Dr Linda Wyatt has infected with the strain of disease she was developing to be a cure for AIDS. However, this particular rat escapes from its cage. Unnoticed because the researcher is murdered, it makes its way out of the building. There it is spotted by Screed, who is hunting his dinner.
Screed has already caught a regular grey rat for himself. The white rat strikes his eye, however; and he puts down the rat in his hand in order to pursue the lab rat. When he catches it and drains its blood, he becomes infected by the disease it carries.
As a result, Screed falls mortally ill. Before he dies, he passes the infection on to his friend, Javier Vachon.
Detective Nick Knight discovers the body of the rat in the alley by the laboratory. When he picks it up, he himself becomes infected. When he then goes to the Raven and drinks some blood from LaCroix's glass, he passes the infection on to him; and, from there, it passes to other vampires until Dr Natalie Lambert is able to find a cure.
The white rat is often referred to by fans as "the Ratsie Wot Killed Screed".
The following are works of fan fiction that feature the white rat among their characters.