That book was accidentally destroyed...

That book was accidentally destroyed maliciously.

This is a quote from the movie "Despicable Me". The humor lies in the juxtaposition of the two words "accidentally", and "maliciously". Accidentally denotes that something happened by chance, or was not intentional. Maliciously denotes that the thing happened intentionally, and with desire to do ill. Using both of these words about the same event is irony.