While children dress up as ghosts and goblins for halloween and get their bags and orange plastic pumpkins filled with candy, there's a ghoul in the night sky above and it's called Algol, the Demon Star... Algol is in the constellation Perseus.
Algol. In October, be on the lookout for Algol — the “Demon Star” — so named because of its regular change in brightness. Algol is a variable star that undergoes very regular intervals between its maximum and minimum brightness.