When mouse moving, have movement stop before entering a teleporter. This would be similar to traps, in where you cannot automatically trigger one with mouse movement. It would bring you to the square adjacent to it. (Reason for suggestion: Round a corner with some fog of war, mysterious portal shows up, automatically walks into mysterious portal. Character dies a terrible death.)
IDK if I would do it with the Satanic Displacement Glyphs, but it definitely seems reasonable with Mysterious Portals, since those are pretty much always high level areas.
