What does Islam say about the ruling on someone who puts a knife to another person's face while joking?

There is no harm in joking as long as it does not involve something forbidden, such as lying, frightening a Muslim, or harming him. What is prohibited is excessive joking or constantly engaging in it, because it leads to much laughter which deadens the heart and diminishes respect. The Prophet, peace be upon him, used to joke, and he would only speak the truth. Lying in jokes is forbidden, for "Woe to him who speaks and lies to make people laugh thereby." Adding ugly speech increases the gravity of the matter, for "The believer is not a slanderer, nor a curser, nor an obscene speaker, nor an evil speaker." Do not joke except with someone you trust, as misunderstanding may lead to problems. As for carrying weapons, "Whoever points an iron object at his brother, the angels curse him," and "None of you should point a weapon at his brother," and "Whoever carries weapons against us is not one of us."