The most dangerous predator of sharks are...
...larger sharks!
The shark may also be a prey of killer whales, giant squids and even giant octopus.
Recently it was confirmed, through a night video recording, that the missing small sharks in a big tank of an US aquarium were beeing eaten, during the night, by an octopus that was in the same tank.
Q.E.D.
Post script:
I forget to mention the most obvious enemy of sharks: Homo sapiens sapiens.
The collective noun for 'stingrays' is a fever of stingrays.
...everything.
The enemys of the gods were the titans and those who worked with them
Crabs are scavengers; they will eat stingrays if the stingrays are already dead.
his arch enemys are shadow, scourge, dr.eggman, and silver
stingrays do not bite they have a stinger in the tale
No,stingrays are NOT vertebrates.They have cartilage,not bones.
stingrays that aren't poisnous
Are there stingrays in Louisiana? In the gulf of Mexico
Stingrays can be up to 20 different colours
a group of stingrays. fever is the collective noun
Yes there are stingrays that can't sting!