This comic strip has been making its way around the internet:
[![Carl and Steve dinosaur comic][1]][1]

The final panel (which was added later) is clearly implying that Steve is watching the asteroid or comet that would eventually create the [Chicxulub crater][2] and cause the [K-T extinction event][3].

Obviously it's just a joke, but I'm curious about the astronomy involved. Wikipedia says the [Chicxulub impactor][4] is thought to have been a 10-15 km diameter object. Would it have been visible to a (human) naked eye before impact? And if so, would it have appeared like a star that grew brighter and brighter each night?


  [1]: https://i.sstatic.net/UKN93.jpg
  [2]: https://en.wikipedia.org/wiki/Chicxulub_crater
  [3]: https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event
  [4]: https://en.wikipedia.org/wiki/Chicxulub_impactor