In the realm of DC comics, Batman is the rich grandad of the lot - created only four years after DC started printing superheroes proper. The main comic has been running for longer than most of us have been alive, let alone comic fans, meaning there is an ungodly supply of Bat-themed joy for any willing soul to make their way through.
However, this longevity does also have some downsides. When Batman was first introduced, it was into a world that was drastically different to modern times, in terms of what would be considered kind of a dick move - calling disabled people evil, for example.
More than that, the fact that Batman has existed for such a long time means people have to use weird and wild characters and plots to attempt to create something new - or at least not do the same comic that was done twenty odd years ago. They always have interesting results, but also more often than not leave you wondering how the whole thing came to be in the first place.
Be it through a strange character, plot, or premise, these are a series of comics that you will never forget - even if you really, really want to.