Final answer:
The violent incident in the Senate over Kansas was the caning of Charles Sumner.
Step-by-step explanation:
The violence that erupted in the Senate over Kansas was known as the caning of Charles Sumner. This incident occurred in 1856 when Massachusetts Senator Charles Sumner delivered a speech criticizing the pro-slavery forces in Kansas. In response, South Carolina Representative Preston Brooks attacked Sumner on the Senate floor, severely beating him with a cane.