Resident evil 5

Chris Redfield returns and heads to Africa where the latest bioterrorism threat is transforming the people into mindless creatures. 

 As Chris and Sheva make their way aboard the tanker, they come across Excella, who escapes, but drops a case of syringes. Sheva holds on to a number of them. When Chris and Sheva arrive on the main deck of the tanker, Wesker, through the tanker's intercom, reveals he has betrayed and infected Excella with Uroboros. She mutates into a giant monster which Chris and Sheva eventually defeat. Jill radios in and informs Chris and Sheva that Wesker must regularly take precisely measured doses of a drug to maintain his superhuman strength and speed; a larger or smaller dose would act as poison for Wesker. Sheva then realizes the syringes she recovered from Excella are doses of that drug. Chris and Sheva follow Wesker to a bomber aboard the tanker loaded with missiles containing the Uroboros virus. Eventually, the two are able to subdue Wesker long enough to inject him with additional doses. Wesker attempts to escape on the bomber, but is followed by Chris and Sheva who disable the bomber, causing it to crash land in a volcano. An enraged Wesker exposes himself to Uroboros, and pursues Chris and Sheva through the volcano. Chris and Sheva fight and weaken Wesker to the point where he falls into the lava.