Batman was created in 1939 by cartoonist Bob Kane and his writer friend Bill Finger. Originally based on pulp characters THE SHADOW and ZORRO he was dark and mysterious.
In Detective Comics 31 dated Sept 1939 he faces off against werewolves and vampires-- the supernatural was introduced to mainstream superhero comics. He dispatches his enemies in this series with the aide of a .45 automatic.
Batman soon toned down his violent ways and adopted the first kid sidekick in comics in the form of Robin the Boy Target.
Still, the covers of the time reflected the mysterious dark night adventures of the character. In this particular issue The Joker is killed by Batman (ahem, accidently).
Pretty soon, however, Batman's covers and stories started to get goofy:
and sometimes ridiculous
While some might argue fun-- and I admit if I was standing at the corner drugstore and saw a Batman cover where he's now a baby I'd likely buy it to find out why-- and then throw it in the trash in disgust.
Many people fault the 1966 Adam West show with bringing this absurdity to Batman but as you can see from these covers done years before the show that was already the road the character was on.
In fact many of the covers appearing at the time of the show were dark in theme;
But when the show was cancelled they went all out-- and Batman became more of a horror title than a superhero one:
and a particular favorite of mine
How Many Ways Can A Robin Die?
Well-- quite a few actually-- and you'd have to read this great book to find out.
I think the horror element is what lured me to Batman-- the mix of genres, the gothic atmosphere-- to me that's the real Batman.