Someone else mentioned it in an earlier post.
The situation is this. Someone makes a statement like "I pass the ball when I play PG, because that's what a PG is supposed to do."
But they speak it like this "I pass the ball when I play PG? Because that's what a PG is supposed do." They raise their voice in that first part, as if it's a question. You'll hear it in movies and television, particularly from bad actors. Every line is spoken like that.
"I saw the vampire? So I staked him in the heart."