Surely yes, but we haven't been around long enough or been close enough to observe it. The swallowing of stars - and any planets that go with them - is almost certainly the source of energy powering quasars, however.

I don't know of any stars or planets that have gone into black holes, but there's a lot I don't know about black holes. I read about black holes in www.wikipedia.org .

I'm still not sure if scientists have seen stars going into black holes, but I think maybe they have. I don't think scientists have seen planets going into black holes, because scientists are only recently finding evidence for planets outside our own solar system, and they're so far away that scientists can't actually see them.