Call the Lurker at the Threshold

You arrange 42 specially made votive candles about a threshold, door, or other enclosure. You then light each in turn while chanting ancient words of calling and binding. At the completion of the spell, you call the Lurker at the Threshold, who appears within an otherworldly darkness covering the enchanted portal.

The Lurker at the Threshold is a mysterious entity able to answer questions that you pose regarding the portal into which it has been called. For example, you can ask it whether and how the portal is locked or trapped, where its key might be, what might be on the other side, where similar portals are located, or you can ask it questions about those who have passed through the portal recently.

You may ask as many questions as you wish, but for each word the Lurker utters, a candle gutters out. When all candles have been extinguished the spell ends and the Lurker is dismissed back to the otherworldly dimension from which it came. Fortunately, the Lurker is a laconic entity.

If you cast this spell two or more times before finishing your next long rest, there is a cumulative 25 percent chance for each casting after the first that the Lurker answers according to its own whims rather than giving a strictly truthful answer. The DM makes this roll in secret each time you ask a question.