Why did the Goblin apply to be a mailman?

Because he was great at delivering scary letters

Why did the mummy always use fabric softener?

Because he didn't want any more static cling with his bandages!

What do you call a zombie who tells jokes?

A dead-pan comedian.

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

Because he kept reanimating the classics and they didn't want any more shelf-life issues.