Can apples kill you?

Yes, apples can kill a person. How?

If a box full of apples falls on someone's head, it may break his neck and he will pass away.

As far as the excess of eating apples is concerned, keep in mind that excess of everything is bad, it is harmful. But I don’t think that it will kill a person.

By the way, I remember an incident that Imam Muslim, who was a great Imam of Hadith, his book is also included in six authentic books of Hadith. All night, he was busy studying & solving problems, in the mean times he was eating dates one by one. By the time the signs of dawn appeared, he had eaten the basket full of dates. Excessive consumption of dates proved fatal for him and he passed away (May Allah shower his blessings on his soul). This incident is narrated in different authentic history books.

So anything should be used to a certain extent, its excess is harmful, if not fatal.