Cover the perso in lots of leaves, dirt would be tooo heavy for him/her.
Also spray adhesive does work wonders, I used some lsat year for a dirt mound and it was great. I had a brown shipping balloon bag and sprayed that while putting peat moss on it. It came out fantastic and I acheived what I was looking for.
But I thik leaves are the way to go if your actor is going to be jumping out and scaring people.