In Halloween tradition, what creatures are said to guard tombs and cemeteries?

Gargoyles

What was used to mark the houses of the Israelites in Egypt? Who famously coached Manchester United for 26 years from 1986 until 2013? Which fictional land is featured in the film "The Grinch"? Which chef is famous for popularizing French cuisine worldwide in the 20th century? In Undertale, what flower initially greets the player character?