Why did the Invisible Man get lost at the library?

Because he couldn't find his place in the Dewey Decimal System!

Why did Frankenstein's monster get kicked out of the library?

Because he kept reanimating the classics.

Why did the jack-o-lantern go to the party?

Because it was a gourd time!

Why did the skeleton refuse to go to the party?

Because he had no body to go with.