What is the ruling on ridiculing stories mentioned in the Prophetic Sunnah, and does that amount to disbelief (kufr)?

Whoever intentionally mocks the words of the Prophet, peace and blessings be upon him, knowing that the story is from his حديث (narration), has committed an act of disbelief (kufr) and apostasy (riddah). This is hardly ever done by a Muslim. Mockery might occur from someone who does not know that the Prophet, peace and blessings be upon him, is the speaker. You must avoid intrusive thoughts (waswas) and not occupy yourself with judging people as disbelievers.