The Black Tiger is an enormous spider mutation created by the T-Virus during the Mansion Incident. Early tests on tarantulas found that they would grow to an enormous size, and experienced extremely aggressive and territorial traits. However, they did not have any special abilities, so Albert Wesker ordered them terminated. However, before he could, the T-Virus was broken loose by a mysterious "accident" (actually Wesker himself unleashed the virus), and the Black Tigers escaped the underground labs in the chaos that followed after all the humans were turned into zombies.
Jill Valentine came across two Black Tigers inside a small bar in the Mansion during the Incident and they attacked her. Jill managed to kill them both, but one managed to bite her, and poisoned her. Jill nearly died from the poison but was rescued by a mysterious man, but passed out for several hours.
Another Black Tiger was encountered in the garden outside the Arklay Mansion, where it was once again disposed of by Jill. This spider had eaten several other zombies and infected creatures, and was experiencing a mutation. Luckily, Jill killed it before it could fully mutate further.
A final Black Tiger was encountered in the underground labs and had been injected with a double helping of T-Virus, making it grow even larger then a regular Black Tiger. It chased Jill through the labs, until Jill managed to trap it inside a chamber. She then turn on the security systems, and the Black Tiger was burned to death by flamethrower turrets. No more were encountered after this.