I always found tigers interesting as they are apparently the only species of big cat that actively hunt humans. Others tend to just attack humans if we get too close but otherwise leave people alone.
Sundabarns especially fcking hell
So many Indian and Bengali fisherman got killed by Tigers who stalked them at and attacked inside the water.
Now imagine pitch black darkness in the river!!
Actually all big cats have some chance of turning into a maneater if the circumstances present themselves for it
Generally likely to be an older/injured one, that has lost access to regular prey for whatever reason, and thus forced to try its luck on humans (especially as human population prevalence increases in its vicinity)
But it may not be the case and some just take humans by opportunity that presents itself and grow accustomed to it (and the humans then have to take action against it).
Even (large enough) leopards can:
en.wikipedia.org
Though the (albeit rare) tendency is seen mostly around tigers (sundarbans esp as ryder mentioned), lions (tsavo maneaters come to mind) and jaguars as they are easily physically powerful enough to overwhelm humans (unlike all but the largest of leopards).
Smaller leopards have also been known to go after human children....and avoid adults etc.
But given the total leopard population, its not surprising there are frequent enough instances involving large male leopards.
en.wikipedia.org
When a predator turns "maneater" it is then (unfortunately) fairly important to track it and kill it....as it will have gotten a taste of human and will only get better or used to having people on the menu.
Happened with a grizzly in yellowstone some years back....pictures of the human victim (partially consumed) were quite disturbing to look at....the park warden made the (correct) decision to go kill the bear given the threat it now posed to other people.
These cases are extremely rare though....and humans do magnitudes more damage (incl predation) on bears, big cats and other apex predators in general.