The Trap Door - Seizoen 1-2

Somewhere in the dark and nasty regions - where nobody goes, stands an ancient castle. Deep within this dank and uninviting place lives Berk, the overworked servant of The Thing Upstairs. But that's nothing compared to the horrors that lurk beneath The Trap Door. For there is always something down there, in the dark, waiting to come out...

Don't you open that Trap Door, You're a fool if you dare, Stay away from that Trap Door, Cos' there's somethin' down there!