If you are referring to Schumaker Levy, I think there were 19 strikes. How does a comet crash 19 times over a period of multiple minutes.
In the (a?) previous encounter with Jupiter, the original comet (prediscovery) broke into fragments, Shoemaker–Levy 9 (with letters assigned to each fragment), but all the fragments remained more or less on the same trajectory as before. The fragments arrived for the impacts over a period of six days or so. At the link, the core of the story starts around the 40 minute mark.