Well, the Blue Whale challenge is about unknown people messaging other people "Do you wanna play?". If the person/victim responds or says yes, the game automatically begins. The unknown people(they have a Mickey mouse pfp and their names have "Jonathan Galindo" in it) gives you 50 tasks. 1 task each day. The task sounds easy at first. But, the longer you play, the worst it gets. The tasks gets darker and harder.. Example: carve a whale on your arm, stand at the edge of the bridge, cut your lip, kill an animal, etc. And the final/50th task is to commit suicide, if you don't wanna do it's they'll come find you and kill your family..!!

(I copy and paste this whenever people ask what it is)