What verb used when one's words change something in the future to negative (not directly but somehow mystically)? For example you expect something positive in the future and another person tells you about it and in the future you get something negative and you blame him/her for that word just like they changed the result from positive to negative. Google translate gives these three words: to overlook to witch to bedevil
From your description, it looks like you're describing this kind of situation:
Person A: "Look at him go. Just one more time and he'll have a perfect score."
(He fails the last time.)
Person B: "You jinxed him!"
"Ssh! Don't say it. If you do, you'll jinx it."
From Merriam-Webster's definition of jinx:
: to foredoom to failure or misfortune : bring bad luck to
Sometimes, people will start to talk about something but then, literally, "knock on wood" (or "tap wood") to prevent its mention from jinxing it (bringing it bad luck).