Sacred glyph

Sacred glyphs were one of the three types of drow runes, the other two being house defense glyphs and way-marker runes.

Description
Drow runes were always limned in black, be it with ink, paste, or inlay. The runes were elegant.

Powers
A sacred glyph stored magic and unleashed it when triggered. The magic was triggered when someone who was not a priestess of Lolth passed over the rune. The kind of magic was the same as way-marker runes but included others in addition to them. As a standard these others were the creation of nine rubbery 20 ft (6 m) tentacles similar to Evard's black tentacles, a shadow flares effect, a forcecage effect, a sink effect, a feeblemind effect, a polymorph other effect that turned the subject into a spider, and an effect that turned the rune into an explosive fire trap. Still other effects were devised by runecasters to mark and protect special locations.

Sacred glyphs were used for the purpose of marking and protecting sacred sites to Lolth, which meant valuables like magic items or sources of wealth like a gem node that belonged to the priesthood of Lolth. The only other drow faith that made use of sacred glyphs was the one of Ghaunadaur. However, they used it only rarely and when they used it, they never made use of the forcecage and polymorph other effects but had favorite in the sink effect.

History
By the 14 century DR, the technology to create sacred glyphs was already old.