Can a whale call kill you?

It can, but it would be only by size, rather by eating you or something. Whale sharks are filter feeders, eating only krill and small fish which they filter out of the water using their gills. While their mouths are massive, they don't have big shark teeth and moreover, aren't intent on harming humans whatsoever. It can be very dangerous to swim near the tail of such a gentle giant, as an accidental whack of its tail can already knock you out cold.