Beltane has just passed, and Mayday has begun. There are no specific ghostly associations with Beltane (I won't argue about the spelling because the name predates any defined English spelling system). It's not like Halloween, but it's an important festival in the Pagan calendar.
In Haiti, the 30th April is known as 'Mange les Morts', which, if you know a smattering of French, is a little disturbing. Actually it means 'Feed the Dead', not 'Eat the Dead'.
I tried for a link but there are so many, and none give details. I was amused by how many links give the date as April 31st. Someone's made a mistake and a lot of people have been copying without thinking.
Reminds me of my teaching days.
Oh, and for fans of Bill Plympton's cartoons, it was his birthday too.