Senior Prank Night happened before the school year began at Mystic Falls High School. This happens in the Season 3 episode, The Reckoning, where the seniors go around the school and play pranks, such as placing rat traps on the classrooms floors or gluing shut teachers desks and even putting honey on the door handles.
Klaus crashed the event, however, ruining Elena, Bonnie, Matt, Tyler, and Caroline's plans, while Stefan was forced into becoming the ripper once more. Dana and Chad die at Senior Prank Night because Klaus compelled Stefan to turn his humanity off and kill them. This is also where Tyler is fed blood via Klaus and killed. Bonnie had to find a way to save Tyler in transition into one of Klaus's hybrid's from dying and with the help from Matt later succeeds in saving Tyler as he transitions into Klaus's first successful hybrid.
- This event took place in the Season Three episode The Reckoning.
- This is the episode that Klaus creates his first successful hybrid.
- Dana and Chad are killed by Stefan, under Klaus' orders.