They bite, they kill, they… fight disease?

Crocodiles can kill the HIV virus:

Scientists in Australia's tropical north are collecting blood from crocodiles in the hope of developing a powerful antibiotic for humans, after tests showed that the reptile's immune system kills the HIV virus.

The article goes on to state that a crocodile has a more robust and effective immune system than humans. Antibodies in the crocodile's blood "can kill off a much greater number of HIV viral organisms" than the human equivalent. There are also hopes for curing other maladies, such as antibiotics for ulcer and burn infections.

The reptile's immune system, however, "may be too powerful for humans, and may need to be synthesized for human consumption". Scientists have yet to isolate the HIV-killing component, and therefore cannot know whether it will prove true, or toxic, for humans. But this is an encouraging lead nonetheless.