Can a jellyfish sting kill a shark?

Most likely, yes. A man of war jellyfish has such deadly tenticles full of strong poison that could kill a shark easily.

Another Answer

Possibly, but the man of war jellyfish is more likely to badly injure the shark than kill it. It all depends on the size of the tentacles of the man of war jellyfish and the type of the shark. But it is very likely for the man of war jellyfish to kill a hammer head shark or other smaller species of sharks.